How does stripe prorating work?

Question

From the Stripe documentation when updating a user’s subscription plan:

By default, we proportionally change the subscription. For example, if a customer signs up on May 1 for $ 10, she will be billed in the amount of $ 10. If she then switches to a $ 20 plan on May 15, she will be billed $ 25 on June 1 ($ 20 for renewal and a $ 5 adjustment for the previous month).

Should not be charged June 1, $ 30; $ 20 for renewals and $ 10 (half of $ 20 for half of May) for the previous month? Does Stripe interpret its calculations, or can I not be mistaken in how thinning works?

Answer 1

Another way to look at this:

Within two months, the client must pay

  $ 5 for May 1 to 15
 + $ 10 for May 16 to 31
 + $ 20 for June
 = $ 35 total
 - $ 10 already paid
 = $ 25