How can I swap subscription prices with instance charges without proration/unused time?

[loremipsumyaya]

Hi, I need help with Laravel Cashier for my app. Users can buy two kinds of Stripe Subscriptions called Basic and Pro, for monthly or yearly credits that can be used in the app.

I have a problem when users switch from Basic to Pro:

• If they haven't spent their credits, they should pay right away without any adjustments for the unused time. This is to stop misuse and because credits and time don't mix.

But when I use $user->subscription('default')->swapAndInvoice($newPrice), it changes the bill for the time not used on the old plan, which I don't want if they still have credits.

How can I stop the adjustment for unused time when changing plans?

Thank you very much for your assistance in advance!