We want our credits to be "use or lose" for annual contracts with monthly commitments

The use case is:

-Customer signs an annual contract

-They receive a $5K monthly token top-up, which recurs each month for life of contract

-By end of billing period, they use $4,500 worth of tokens, leaving $500 unused

-On April 12, the unused $500 expires, and a new $5K allocation is issued

It's currently possible to set an expiration date for the wallet, but not for the credits issued.