Originally Posted by gsxr

New nozzles often don't spray perfectly, they need some break-in time. Not always though. But after break-in, the pop pressures typically drop by 2-5 bar compared to new. I'd pop test before installing and write down the numbers, then run then for a few thousand miles, then remove and balance them.

If you balance to begin with, you may need to re-balance a few after break-in (or all of them, if you're trying to set to a specific pressure). Of course this is much easier if you have a pop tester in your garage (~$200 or so). Kinda tough if you're paying a shop to do the work.