diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 4eed9863..7fb5a0f6 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -635,46 +635,6 @@ parameters:
 			count: 1
 			path: src/PhpSpreadsheet/Calculation/Financial/CashFlow/Variable/Periodic.php
 
-		-
-			message: "#^Binary operation \"\\*\" between float\\|string and int results in an error\\.$#"
-			count: 2
-			path: src/PhpSpreadsheet/Calculation/Financial/Coupons.php
-
-		-
-			message: "#^Binary operation \"\\*\" between float\\|string and int\\|string results in an error\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Calculation/Financial/Coupons.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Financial\\\\Coupons\\:\\:couponFirstPeriodDate\\(\\) has no return typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Calculation/Financial/Coupons.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Financial\\\\Coupons\\:\\:couponFirstPeriodDate\\(\\) has parameter \\$maturity with no typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Calculation/Financial/Coupons.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Financial\\\\Coupons\\:\\:couponFirstPeriodDate\\(\\) has parameter \\$next with no typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Calculation/Financial/Coupons.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Financial\\\\Coupons\\:\\:couponFirstPeriodDate\\(\\) has parameter \\$settlement with no typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Calculation/Financial/Coupons.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Financial\\\\Coupons\\:\\:validateCouponPeriod\\(\\) has parameter \\$maturity with no typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Calculation/Financial/Coupons.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Financial\\\\Coupons\\:\\:validateCouponPeriod\\(\\) has parameter \\$settlement with no typehint specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Calculation/Financial/Coupons.php
-
 		-
 			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Calculation\\\\Financial\\\\Depreciation\\:\\:validateCost\\(\\) has parameter \\$cost with no typehint specified\\.$#"
 			count: 1
diff --git a/src/PhpSpreadsheet/Calculation/Financial/Coupons.php b/src/PhpSpreadsheet/Calculation/Financial/Coupons.php
index 5620c327..3fd6c1d2 100644
--- a/src/PhpSpreadsheet/Calculation/Financial/Coupons.php
+++ b/src/PhpSpreadsheet/Calculation/Financial/Coupons.php
@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation\Financial;
 
+use DateTime;
 use PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel;
 use PhpOffice\PhpSpreadsheet\Calculation\Exception;
 use PhpOffice\PhpSpreadsheet\Calculation\Financial\Constants as FinancialConstants;
@@ -73,7 +74,7 @@ class Coupons
             return abs((float) DateTimeExcel\Days::between($prev, $settlement));
         }
 
-        return DateTimeExcel\YearFrac::fraction($prev, $settlement, $basis) * $daysPerYear;
+        return (float) DateTimeExcel\YearFrac::fraction($prev, $settlement, $basis) * $daysPerYear;
     }
 
     /**
@@ -208,7 +209,7 @@ class Coupons
             }
         }
 
-        return DateTimeExcel\YearFrac::fraction($settlement, $next, $basis) * $daysPerYear;
+        return (float) DateTimeExcel\YearFrac::fraction($settlement, $next, $basis) * $daysPerYear;
     }
 
     /**
@@ -322,7 +323,7 @@ class Coupons
             FinancialConstants::BASIS_DAYS_PER_YEAR_NASD
         );
 
-        return (int) ceil($yearsBetweenSettlementAndMaturity * $frequency);
+        return (int) ceil((float) $yearsBetweenSettlementAndMaturity * $frequency);
     }
 
     /**
@@ -379,28 +380,33 @@ class Coupons
         return self::couponFirstPeriodDate($settlement, $maturity, $frequency, self::PERIOD_DATE_PREVIOUS);
     }
 
-    private static function couponFirstPeriodDate($settlement, $maturity, int $frequency, $next)
+    private static function monthsDiff(DateTime $result, int $months, string $plusOrMinus, int $day, bool $lastDayFlag): void
+    {
+        $result->setDate((int) $result->format('Y'), (int) $result->format('m'), 1);
+        $result->modify("$plusOrMinus $months months");
+        $daysInMonth = (int) $result->format('t');
+        $result->setDate((int) $result->format('Y'), (int) $result->format('m'), $lastDayFlag ? $daysInMonth : min($day, $daysInMonth));
+    }
+
+    private static function couponFirstPeriodDate(float $settlement, float $maturity, int $frequency, bool $next): float
     {
         $months = 12 / $frequency;
 
         $result = Date::excelToDateTimeObject($maturity);
-        $maturityEoM = Helpers::isLastDayOfMonth($result);
+        $day = (int) $result->format('d');
+        $lastDayFlag = Helpers::isLastDayOfMonth($result);
 
         while ($settlement < Date::PHPToExcel($result)) {
-            $result->modify('-' . $months . ' months');
+            self::monthsDiff($result, $months, '-', $day, $lastDayFlag);
         }
         if ($next === true) {
-            $result->modify('+' . $months . ' months');
+            self::monthsDiff($result, $months, '+', $day, $lastDayFlag);
         }
 
-        if ($maturityEoM === true) {
-            $result->modify('-1 day');
-        }
-
-        return Date::PHPToExcel($result);
+        return (float) Date::PHPToExcel($result);
     }
 
-    private static function validateCouponPeriod($settlement, $maturity): void
+    private static function validateCouponPeriod(float $settlement, float $maturity): void
     {
         if ($settlement >= $maturity) {
             throw new Exception(Functions::NAN());
diff --git a/tests/data/Calculation/Financial/COUPDAYBS.php b/tests/data/Calculation/Financial/COUPDAYBS.php
index 260783fa..f41d3620 100644
--- a/tests/data/Calculation/Financial/COUPDAYBS.php
+++ b/tests/data/Calculation/Financial/COUPDAYBS.php
@@ -205,4 +205,18 @@ return [
         4,
         4,
     ],
+    [
+        5,
+        '05-Apr-2019',
+        '30-Sep-2021',
+        2,
+        0,
+    ],
+    [
+        5,
+        '05-Oct-2019',
+        '31-Mar-2022',
+        2,
+        0,
+    ],
 ];
diff --git a/tests/data/Calculation/Financial/COUPDAYS.php b/tests/data/Calculation/Financial/COUPDAYS.php
index c72d26c1..caba56e5 100644
--- a/tests/data/Calculation/Financial/COUPDAYS.php
+++ b/tests/data/Calculation/Financial/COUPDAYS.php
@@ -219,4 +219,18 @@ return [
         4,
         4,
     ],
+    [
+        180,
+        '05-Apr-2019',
+        '30-Sep-2021',
+        2,
+        0,
+    ],
+    [
+        180,
+        '05-Oct-2019',
+        '31-Mar-2022',
+        2,
+        0,
+    ],
 ];
diff --git a/tests/data/Calculation/Financial/COUPDAYSNC.php b/tests/data/Calculation/Financial/COUPDAYSNC.php
index ca611475..e8500263 100644
--- a/tests/data/Calculation/Financial/COUPDAYSNC.php
+++ b/tests/data/Calculation/Financial/COUPDAYSNC.php
@@ -219,4 +219,21 @@ return [
         4,
         4,
     ],
+    [
+        175,
+        '05-Apr-2019',
+        '30-Sep-2021',
+        2,
+        0,
+    ],
+    // Excel and LibreOffice return 175 for the following calculation.
+    // Gnumeric returns 176.
+    // My hand calculation, hardly guaranteed, agrees with Gnumeric.
+    [
+        176,
+        '05-Oct-2019',
+        '31-Mar-2022',
+        2,
+        0,
+    ],
 ];
diff --git a/tests/data/Calculation/Financial/COUPNCD.php b/tests/data/Calculation/Financial/COUPNCD.php
index 8dee4c0a..d690525c 100644
--- a/tests/data/Calculation/Financial/COUPNCD.php
+++ b/tests/data/Calculation/Financial/COUPNCD.php
@@ -219,4 +219,32 @@ return [
         4,
         4,
     ],
+    [
+        44651,
+        '30-Sep-2021',
+        '31-Mar-2022',
+        2,
+        0,
+    ],
+    [
+        44834,
+        '31-Mar-2022',
+        '30-Sep-2022',
+        2,
+        0,
+    ],
+    [
+        43738,
+        '05-Apr-2019',
+        '30-Sep-2021',
+        2,
+        0,
+    ],
+    [
+        43921,
+        '05-Oct-2019',
+        '31-Mar-2022',
+        2,
+        0,
+    ],
 ];
diff --git a/tests/data/Calculation/Financial/COUPPCD.php b/tests/data/Calculation/Financial/COUPPCD.php
index e906f147..88b93af5 100644
--- a/tests/data/Calculation/Financial/COUPPCD.php
+++ b/tests/data/Calculation/Financial/COUPPCD.php
@@ -219,4 +219,18 @@ return [
         4,
         4,
     ],
+    [
+        43555,
+        '05-Apr-2019',
+        '30-Sep-2021',
+        2,
+        0,
+    ],
+    [
+        43738,
+        '05-Oct-2019',
+        '31-Mar-2022',
+        2,
+        0,
+    ],
 ];