I think the measurement is fixture units, not physical fixtures. You'd have to look up what each one of those things is designed for and then total them.
An arrester is only needed close to fast closing valves. The ones that are most likely to make any difference are those for the washing machine. They work best, the closer they are. The idea is to absorb the piston effect of the flowing water when it slams against a fast closing valve. The dish washer could possibly use one, too. Too far from the actual valve, and there's enough force to still give problems.