Can't seem to change $form

So I am trying to use a hook to add change the price.

here is my code

add_filter("gform_pre_submission_filter", "change_price");
function change_price($form){

    $price  = $_POST["input_2"]; //player 1 email

	$coupon = trim( $_POST['input_6'] );

   $codes = array(

   			'27' => 'abc27',
            '25' => 'def25',
            '23' => 'xyz23',
            '21' => 'abc21',
            '19' => 'def19',
            '17' => 'xyz17',
            '15' => 'abc15',
            '13' => 'def13',
            '11' => 'zyx11',
            '9' => 'abc9'

   );

   $discounts = array_flip($codes);

   	if( !empty($coupon) && in_array($coupon, $codes) )
   	{
   	 	if( $form["input_3"] == 'Regular')
		{
			//$form["input_3"] == 'Regular|'.$discounts[$coupon];
		}
		else
		{
			//$form["input_3"] == 'Large|'.$discounts[$coupon];
		}

	}
  	//var_dump($form['fields']);

	//echo $form['fields'][0]['choices'][0]['price'];
	//exit;
    //returning modified form object

    foreach($form["fields"] as &$field){

		if($field["id"] == 3){

            $field["basePrice"] = '$'.$discounts[$coupon];
			$field['choices'][0]['price'] = '$'.$discounts[$coupon];
			$field['choices'][1]['price'] = '$'.$discounts[$coupon];

			//echo "yes";

        }

		//var_dump($field);

		//exit;
	}
	//$form['fields'][0]['choices'][0]['price'] = '$'.$discounts[$coupon];
	//$form['fields'][0]['choices'][1]['price'] = '$'.$discounts[$coupon]; 

	//var_dump($form['fields']);

	//exit;

    return $form;
}

here is the form:
https://www.autoeye.org/test

If I dump the form variable the values get changed, but now I'm not sure if they are the values I'm supposed to be changing.
If I just submit the form, it's like nothing happened.

I have most of it commented out because I'm trying to trouble shoot.

I don't know where I'm giong wrong. Please help.

If I for example try the coupon code for $15 it returns this:

array(11) {
  [0]=>
  array(56) {
    ["adminLabel"]=>
    string(0) ""
    ["adminOnly"]=>
    string(0) ""
    ["allowsPrepopulate"]=>
    bool(false)
    ["defaultValue"]=>
    string(0) ""
    ["description"]=>
    string(0) ""
    ["content"]=>
    string(0) ""
    ["cssClass"]=>
    string(0) ""
    ["errorMessage"]=>
    string(0) ""
    ["id"]=>
    int(3)
    ["inputName"]=>
    string(0) ""
    ["isRequired"]=>
    bool(true)
    ["label"]=>
    string(11) "Choose Size"
    ["noDuplicates"]=>
    string(0) ""
    ["size"]=>
    string(6) "medium"
    ["type"]=>
    string(7) "product"
    ["postCustomFieldName"]=>
    string(0) ""
    ["displayAllCategories"]=>
    bool(false)
    ["displayCaption"]=>
    string(0) ""
    ["displayDescription"]=>
    string(0) ""
    ["displayTitle"]=>
    string(0) ""
    ["inputType"]=>
    string(6) "select"
    ["rangeMin"]=>
    string(0) ""
    ["rangeMax"]=>
    string(0) ""
    ["calendarIconType"]=>
    string(0) ""
    ["calendarIconUrl"]=>
    string(0) ""
    ["dateType"]=>
    string(0) ""
    ["dateFormat"]=>
    string(0) ""
    ["phoneFormat"]=>
    string(0) ""
    ["addressType"]=>
    string(0) ""
    ["defaultCountry"]=>
    string(0) ""
    ["defaultProvince"]=>
    string(0) ""
    ["defaultState"]=>
    string(0) ""
    ["hideAddress2"]=>
    string(0) ""
    ["hideCountry"]=>
    string(0) ""
    ["hideState"]=>
    string(0) ""
    ["inputs"]=>
    NULL
    ["nameFormat"]=>
    string(0) ""
    ["allowedExtensions"]=>
    string(0) ""
    ["captchaType"]=>
    string(0) ""
    ["page_number"]=>
    string(0) ""
    ["captchaTheme"]=>
    string(0) ""
    ["simpleCaptchaSize"]=>
    string(0) ""
    ["simpleCaptchaFontColor"]=>
    string(0) ""
    ["simpleCaptchaBackgroundColor"]=>
    string(0) ""
    ["failed_validation"]=>
    string(0) ""
    ["productField"]=>
    string(0) ""
    ["enablePasswordInput"]=>
    string(0) ""
    ["maxLength"]=>
    string(0) ""
    ["enablePrice"]=>
    bool(true)
    ["basePrice"]=>
    string(3) "$15"
    ["disableQuantity"]=>
    bool(false)
    ["formId"]=>
    int(1)
    ["pageNumber"]=>
    int(1)
    ["conditionalLogic"]=>
    bool(false)
    ["choices"]=>
    array(2) {
      [0]=>
      array(4) {
        ["text"]=>
        string(18) "Regular 13" x 2.5""
        ["value"]=>
        string(7) "Regular"
        ["isSelected"]=>
        bool(true)
        ["price"]=>
        string(3) "$15"
      }
      [1]=>
      array(4) {
        ["text"]=>
        string(14) "Large 13" x 4""
        ["value"]=>
        string(5) "Large"
        ["isSelected"]=>
        bool(false)
        ["price"]=>
        string(3) "$15"
      }
    }
    ["enableChoiceValue"]=>
    bool(true)
  }

But does not reflect that in the database or query string.