Charge for additional users at the end of the billing period

Charge for additional users at the end of the billing period

Hey there

I'm selling a product where the customer for example pays $5 per user per month in an annual subscription. The customer can add and remove users during the subscription period. If he adds 1 user, prorated billing kicks in and charges $5 / month for the rest of the period and if he removes 1 user he'll get a refund of $5 / month for the rest of the period. These changes can happen multiple times a month. My question is: Is there a way to only "remember" the amount that needs to be charged / refunded but send the actual invoice at the end of the subscription period? If not, the customer gets a new invoice every time he adds / removes a user. Ideally he should get an invoice at the beginning and one at the end of the subscription period.

Cheers!