If you create a new lease for a tenant in the middle of the month and have it start on a different date than today's date, the system will create a prorated rent amount.
It prorates based on the exact number of days between the billing dates.
Example:
On June 5th, you create a new lease that bills on the 1st. So the next bill date is July 1st. It will generate a charge based on the number of days between June 1st and July 1st, minus the days that have already passed. So in this case, there are 30 days in June, minus 4 that have already passed, so 26. So it will charge 26/30 * Rent amount.