Weekly prices and monthly prices that are established in OR and price is consistent for each week/month no matter how many days are booked within that week/month.
As far as I know, the channels do not, easily and reliably, support true monthly pricing and instead we suggest using Length of Stay (LOS) discounts. This method would support 28 or 31 or whatever number of nights you select, but does not support a month of "January" or "February" rent.
https://www.ownerrez.com/support/articles/length-of-stay-discounts