For all of the club/shaft gurus out there, I have an interesting scenario.

Short story long; In a moment of weakness last week I ended up "damaging" my AP2 6-iron to the point of restoration. I took it to a local club fitter because he had a matching KBS Tour 90 (Stiff) shaft in stock and it would be a simple replacement. Upon arrival, we noticed that the stamped Tour90 (Stiff) shaft that he had in stock did not match the shaft that I currently had in my 6-iron, which was fitted and custom built/ordered from Golfsmith in Michigan.

The difference; The step pattern. There appeared to be an extra step or two in the pattern.

So. We grabbed a KBS Tour shaft (unfortunately all we had on hand was a shaft fit for a Wedge) and the stepping had matched perfectly with my current Tour 90 S. Onto the next discovery. To try and de-bunk if the appropriate shafts were put in my club from the start, we pulled the grip and peeled back a layer of tape to reveal the factory sticker pointing out what the shaft actual had been. Sure enough, KBS Tour90 Stiff.

The ultimate question; Over the years since purchase (early 2015 if I recall correctly) has the KBS Tour 90 model shaft changed in regard to step pattern? Is this simply an occurrence that maybe the wrong shafts had been put in from the start, or wrongfully labeled?

I hooked up to the launch monitor with the different stepped shaft that is a Tour 90S and all angles/numbers align with where they are supposed to be.

Any opinions welcome to this mystery. (I am not a robot) :)