Stripe.com payment integration module

[mario75]

Hi! Thank you for a great plugin and for all the work put into making it and resolving all the errors and requests from the community! I really appreciate it! But I need some help!
I'm using Zen-Cart v1.5.7c. Therefore I had to use Stripe.com Payments Integration Version 2.1.14 from Zen-Cart plugin section, as it is the latest one that supports my version of ZC.

All went well for a few months, the payments were processed correctly until the day I wanted to use a discount coupon. Zen-Cart showed the correct amount on the checkout page (I'm using the standard three pages checkout system), but Stripe received the amount without the discount and the client paid the full amount without the discount.

I have read the entire topic and I have found that this problem was also reported much earlier than version 2.1.14 of the plugin, and they were told that this would be addressed and corrected in later versions.
But here I am, with no immediate plans to upgrade Zen-Cart, having the same problem with discount coupon not being included in the amount that Stripe requests from client.
I have also read about editing the

function pre_confirmation_check() {

but I'm not sure what to edit, or if I should edit at all, and also about using

$calculatedTotal = $order_total_modules->pre_confirmation_check(true);

but I need help making those edits for Stripe.com plugin version: 2.1.14 to work for my version of Zen-Cart.
Thank you in advance!