One thing is the trajectory is very high with a regular flex for that high of a swing speed. The other is difficulty hitting it straight.

The charts tell one that too stiff of a flex causes a slice/fade and too flexible causes a draw/hook (this was on a website for fitting). This is assuming you have a proper swing path. This was true for a couple Burner 5H clubs I had. One was "M" (senior) and I would pull it. The other was stiff but I hit it dead straight. Drivers (personal experience) - My current driver is a Burner Draw M flex and I hit it dead straight or even a small pull (it also has a 45" shaft so it may not exactly be senior flex). With a neutral face club, I would hit a stiff pretty straight but the distance was 20 yards shorter. A regular had a high trajectory when straight and my distance shot was a power fade. 3 woods told a different story - my current one is an R7 with a 70 gram r flex shaft and I hit it dead straight. I tried a later model Burner 3 wood with M flex and it exaggerated a slice (I brought it back to the store and got the R7). If the shaft is too flexible it will exaggerate a slice or hook (proof was a 975 driver with lite regular flex that I tried out a couple years ago - I had a nasty slice with it).

When you go for a fitting compare them on a launch monitor (ball speed, launch angle, shot pattern).