Q regarding AR Recurring Invoice Recycle Process

Hi,

I have a Q about AR Recurring Invoice Recycle Process. If frequency is selected Monthly (MO), how many days gap would next invoice have? Would it be 30 or 31 or will it just recycle it in beginning/end of the next month? For Ex: If a recurring AR invoice was entered:

1. End of Jan - say Jan 31

2. Mod of Jan - say Jan 15

When would the recurring invoice get generated? Thank you.