Consider overage terms checks for future dated subscriptions.

The following discussion from !14538 should be addressed:

• @jhyson started a discussion: (+1 comment)

  question (non-blocking): I'm curious how this will work with someone that has future dated subscription changes (given the use of the operable_version_on_date) method. For example, if I renew my subscription, and opt out of usage billing -- the flag will still be enabled until my renewal happens, is that right?