That's the "flat rate mechanic " method- - - -quick and accurate, and most of Dad's mechanics did it that way back in the 1950s. Unless a radical racing cam with lots of overlap is involved, it works great.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!