Removing javascript alerts on Checkout page Change in memberships

Hi,

Thanks for this wonderful plugin. Saved me hours of work. However, I have 3 questions:

1. Is there a way to remove js alerts–they are ugly–and replace them with a page redirect without touching the preheaders of the checkout page.

2. Does the plugin support the following use case: If a user cancels his monthly subscription. He should be allowed to use the service for the current month as he already paid for it?

3. And finally another question about a special usecase: If a user upgrades his subscription plan to a higher plan, do you charge only the difference between the two plans for the current month? If the user downgrades plans, do you offer him the new plan without charge for the current month as he already paid for the highest plan for the current month?

Thanks,

https://wordpress.org/plugins/paid-memberships-pro/