Related my earlier comment about moving $REQUIRED_ROWS to a value into the controller.  You could eliminate REQUIRED_ROWS here altogether by doing something like this:

foreach ( STATIC::$dataFields as $formFieldName => $varName ) {
    if ( empty( $formValues[$formFieldName] ) {
        continue;
    }
    foreach ( $formValues[$formFieldName] as $i => $value ) {
        $order = $i + 1;  // because input data start from 0
        $data[$order][$varName] = $value;
    }
}

Or just pass in a $row argument.