subscriptions: 1 user, multiple profile s
Using Jamroom
When a user purchases a subscription, their quota changes. The quota that changed will stay in that quota for as long as the subscription is live, then it will revert to whatever is set in the QUOTA CONFIG tab for that profile to change to once its subscription ends. When money is received from a subscription payment the end date of the subscription is pushed out longer.
If you allow your subscription quotas to be signed up to, no one will buy them. dont do that.
A purchase of a subscription should only change one quota, not multiple at the same time. I've not done extensive testing on multiple power user quotas purchasing subscriptions so don't have a model to answer this question.