I know it's easy to get a false weak. But how bout false stiff? I was tuning today and  added some weight and it still showed stiff. I added more and got the bare shaft to shoot really good out to 25 yards +, but the fletched 250 gr broadheads kept going way  left. (I am right handed) Running out of length and weight I couldnt get the boradheads to shoot down the center. (A't that point I had 100 gr brass inserts and 250 gr point) After a few hours I went way in the other direction. 50 grains less using long 50 gr alum inserts and still the 250 gr point. The length and and 50 grains less weight combine to add a lot of stiffness. Surprisingly that really did it, the arrow flight with broad heads is down the center. Bare shaft still showing just a tad stiff maybe but the field point, bar shaft and broad heads all impact the same spot. I

Yes I have had false stiff readings from bareshafting.I had bought some used carbons that were already cut to length and showing alittle stiff.So I thought I could add more upfront weight to weaken the spine.They got worse and showing even stiffer the more weight I added.Carbons recover much quicker then aluminum or wood they were bouncing off the riser instead of flexing around it.I did tune the same carbon to that bow but started with full length and they ended up about 2" longer.I found on some bows the closer the front weight is to the riser and showing stiff adding more weight made it worse.This was on a longbow cut about 1/8" off center.May have tuned alright on a recurve cut past center?