The old timers know this. I've done it literally hundreds of times.
Yesterday, the mailbox gave up a nice, older box call I bought on eBay. It's a higher end, production call. I unpacked it and gave it a few scrapes. Nuh uh. Went back and grabbed my "box call repair kit"...………..better known as a "Phillips head screwdriver". I eyeballed the paddle and it looked to be sitting just a whisker low on the screw side. 1/4 turn counter clockwise...….run the call. Nope. Another 1/4 turn...…...run the call. Sorta. But nope. Another 1/4 turn counter clockwise. There it was !!! 3/4 of a turn of a screwdriver took the screech owl out and filled it up with turkey.
Back when I was doing sports shows, conventions and expos for a call company, I spent a lot of time with the screwdriver out on my Leatherman. When box calls are being made and tuned 1000 or 5000 at a time, they won't always get that last little tweek that turns "oh, OK" into "oh, WOW !!".
I ALWAY start by going counter clockwise. Better to over-loosen right from the get-go than over-tighten. It IS possible to split an end block if you go all gorilla tightening. 1/4 turn at a time, whichever way you're going...….keeps you from over-tightening AND keeps you from going PAST the sweet spot.