well...first it's JBJ not JBL.
Uhh...there is no industry standard for installation as there are too many variables. Charge what you can...whatever the market will bear. Of course there is a limit to that last statement. You don't want to price yourself out of the project.
I think you might have of missed my point of getting some professional training...not just for wiring etc. but for creating proposals and management of your AV firm.
Check out
www.cedia.net