Hello,

Greetings for the day!

The answers to your questions are:

- Yes, that is right. If you stack two codes, then you will receive 400 credits every month for a lifetime.
- The credits reset in the first week of every month. They don't roll over but reset to your monthly credit limit every month.

Please let me know if you have any other questions, and I will be glad to assist!

Thank you,
Robin