I do not use a contract,although I think they are every important to a fleet washer in building his business.
Did you ask if they had a report in what they expected a fleet washer to apply by?Some have a written statement in what they want done,like windows cleaned inside and out,mirrors cleaned spotless and so on.

I did a search on the web and found some helpful things in building a bid sheet,just type in fleet washing contracts.

When In Doubt Think It Out