diff --git a/src/PhpSpreadsheet/Cell/Coordinate.php b/src/PhpSpreadsheet/Cell/Coordinate.php
index b2dd65c4..fac3c629 100644
--- a/src/PhpSpreadsheet/Cell/Coordinate.php
+++ b/src/PhpSpreadsheet/Cell/Coordinate.php
@@ -47,15 +47,17 @@ abstract class Coordinate
      *
      * @param string $coordinates eg: 'A1', '$B$12'
      *
-     * @return array{0: int, 1: int} Array containing column index and row index (indexes 0 and 1)
+     * @return array{0: int, 1: int, 2: string} Array containing column and row index, and column string
      */
     public static function indexesFromString(string $coordinates): array
     {
-        [$col, $row] = self::coordinateFromString($coordinates);
+        [$column, $row] = self::coordinateFromString($coordinates);
+        $column = ltrim($column, '$');
 
         return [
-            self::columnIndexFromString(ltrim($col, '$')),
+            self::columnIndexFromString($column),
             (int) ltrim($row, '$'),
+            $column,
         ];
     }
 
diff --git a/src/PhpSpreadsheet/Collection/Cells.php b/src/PhpSpreadsheet/Collection/Cells.php
index 8555d09b..20fccf48 100644
--- a/src/PhpSpreadsheet/Collection/Cells.php
+++ b/src/PhpSpreadsheet/Collection/Cells.php
@@ -96,12 +96,7 @@ class Cells
      */
     public function has($cellCoordinate)
     {
-        if ($cellCoordinate === $this->currentCoordinate) {
-            return true;
-        }
-
-        // Check if the requested entry exists in the index
-        return isset($this->index[$cellCoordinate]);
+        return ($cellCoordinate === $this->currentCoordinate) || isset($this->index[$cellCoordinate]);
     }
 
     /**
@@ -237,7 +232,7 @@ class Cells
         $toRow = $row * self::MAX_COLUMN_ID;
         $fromRow = --$row * self::MAX_COLUMN_ID;
         foreach ($this->index as $coordinate) {
-            if ($coordinate < $fromRow || $coordinate > $toRow) {
+            if ($coordinate < $fromRow || $coordinate >= $toRow) {
                 continue;
             }
             $column = $coordinate % self::MAX_COLUMN_ID;
diff --git a/src/PhpSpreadsheet/Worksheet/Worksheet.php b/src/PhpSpreadsheet/Worksheet/Worksheet.php
index cb2cd06d..4c0237f5 100644
--- a/src/PhpSpreadsheet/Worksheet/Worksheet.php
+++ b/src/PhpSpreadsheet/Worksheet/Worksheet.php
@@ -181,13 +181,6 @@ class Worksheet implements IComparable
      */
     private $conditionalStylesCollection = [];
 
-    /**
-     * Is the current cell collection sorted already?
-     *
-     * @var bool
-     */
-    private $cellCollectionIsSorted = false;
-
     /**
      * Collection of breaks.
      *
@@ -1336,24 +1329,22 @@ class Worksheet implements IComparable
      */
     public function createNewCell($coordinate)
     {
-        [$column, $row] = Coordinate::coordinateFromString($coordinate);
+        [$column, $row, $columnString] = Coordinate::indexesFromString($coordinate);
         $cell = new Cell(null, DataType::TYPE_NULL, $this);
         $this->cellCollection->add($coordinate, $cell);
-        $this->cellCollectionIsSorted = false;
 
         // Coordinates
-        $aIndexes = Coordinate::indexesFromString($coordinate);
-        if ($this->cachedHighestColumn < $aIndexes[0]) {
-            $this->cachedHighestColumn = $aIndexes[0];
+        if ($column > $this->cachedHighestColumn) {
+            $this->cachedHighestColumn = $column;
         }
-        if ($aIndexes[1] > $this->cachedHighestRow) {
-            $this->cachedHighestRow = $aIndexes[1];
+        if ($row > $this->cachedHighestRow) {
+            $this->cachedHighestRow = $row;
         }
 
         // Cell needs appropriate xfIndex from dimensions records
         //    but don't create dimension records if they don't already exist
         $rowDimension = $this->rowDimensions[$row] ?? null;
-        $columnDimension = $this->columnDimensions[$column] ?? null;
+        $columnDimension = $this->columnDimensions[$columnString] ?? null;
 
         if ($rowDimension !== null && $rowDimension->getXfIndex() > 0) {
             // then there is a row dimension with explicit style, assign it to the cell
diff --git a/tests/data/Cell/IndexesFromString.php b/tests/data/Cell/IndexesFromString.php
index c2fe1c09..0a79e47f 100644
--- a/tests/data/Cell/IndexesFromString.php
+++ b/tests/data/Cell/IndexesFromString.php
@@ -5,6 +5,7 @@ return [
         [
             1,
             1,
+            'A',
         ],
         'A1',
     ],
@@ -12,6 +13,7 @@ return [
         [
             1,
             12,
+            'A',
         ],
         'A12',
     ],
@@ -19,6 +21,7 @@ return [
         [
             10,
             1,
+            'J',
         ],
         'J1',
     ],
@@ -26,6 +29,7 @@ return [
         [
             10,
             20,
+            'J',
         ],
         'J20',
     ],
@@ -33,6 +37,7 @@ return [
         [
             35,
             1,
+            'AI',
         ],
         'AI1',
     ],
@@ -40,6 +45,7 @@ return [
         [
             35,
             2012,
+            'AI',
         ],
         'AI2012',
     ],
@@ -47,6 +53,7 @@ return [
         [
             2,
             3,
+            'B',
         ],
         'B3',
     ],
@@ -54,6 +61,7 @@ return [
         [
             2,
             3,
+            'B',
         ],
         '$B3',
     ],
@@ -61,6 +69,7 @@ return [
         [
             2,
             3,
+            'B',
         ],
         'B$3',
     ],
@@ -68,6 +77,7 @@ return [
         [
             2,
             3,
+            'B',
         ],
         '$B$3',
     ],