Sounds like a bill to me.
The tithing settlement actually lists how much someone has tithed, not how much they made.
There is not tithing bill, the show you how much you have paid in in tithing and ask you if that is a full tithe, then they take your word for it.
Greyfoxx, didn't you say you were a former member? If so, why do you not know this answer? Because of this, I am thinking that you were either not a member of were not a practicing member. Please clarify.
Tithing Settlement is an honor based system. There are no records, tax receipts, check stubs, or anything like that. The bishop asks if you are a full tithe payer, and you say yes or no. Whither you are full, part, or non- tithe payer, a discussion usually ensues about the principles of tithing, including sacrifice, obedience, faith, blessings, etc. (see Malachi 3)