Is Accounts Payable and Lease Administration considered Accounting?

AP yes...Leas admin...no

yes

You should include all of your accounting and complimentary experience (depending on exactly what you're dealing with).

You can if you like it's not like they are going to say that lease admin is not accounting therefore it doesn't count. Accounting is all billing aspects...if you write a big number, be prepared to give them that in your work if you are hired.