Hello, has anyone here run into the situation where a days in advance can be variable for billing specifically for the first invoice? For example we could be able to bill the days in advance anywhere from 0-30 days from the start date of the contract. We are trying to avoid creating hundreds of billing schedules. Thank you.

Just create a separate line item for the amount you want to bill in advance. The other line item will then be just the true recurring billing that you have.