Moving tenants didn't give 30 days on Aug 1 - can I prorate to cover extended time at a higher rate?

[Kathlyn Lewis]

Hello oh lovely and generous BP community!

Question that some searching didn't answer.

I'm in Idaho and about to lose tenants who aren't happy with a rent increase - this is fine, we aren't upset to have to get new tenants.  They had a one year lease which clearly states that they have to give 30 days written notice to not renew the lease.

So they are going to be at least 8 days overdue, and we are going to prorate their rent to cover to 30 days.  Here is the  question:

Can we prorate the rent using the new, higher rate that the apartment is going to be rented for?  Or do we have to stick with the rate they have been paying?

Thanks in advance for your help!

Kathlyn