I am a G.M. of a 32 lane center. Every lane gets oiled every day, and we re-oil before evening leagues, so many of them are done twice daily. Bowlers get what is out there, but with our schedule finding some oil usually isn't too hard.
Re-oiling a pair on a Friday or Saturday night would be out of the question, though. We typically have an hour wait for a lane during prime time Friday/Saturday nights. My mechanic is busy getting stops and repairing things in the arcade, or something. It is not cost effective to ask him to drag the 250 pound machine out to oil a pair for some guys who probably can't read ball reaction anyway (140 average, as you put it).
We've also got the Cosmic lights and music going, so most of our league bowlers just come when they can see what they are doing. I have actually never even had the request, either. When teams start getting ready for Nationals I will try very hard to put out the shot on certain days, but never would I dream of doing it when these guys are requesting... Just too busy!