Update subscription plan. how will the fee be calculated?

If I update my subscription plan in the middle of the term, how will the fee be calculated?

It would just update the price for the next cycle as far as I know. For example, if you charge $10 for 30 days then the customer would pay $10 and it would be good for 30 days. If you dropped the charge to $5, then it wouldn’t take affect until their 30 days were up, I believe (so the next charge would be $5 instead of $10 at the end of the 30 days).