My thought on the broadhead weights is that they are probably 160 and 190 before grinding and Grizzly is straight up about weight loss. Not that any of the others are being dishonest they just report the before grinding weight or start heavier and grind to those weights. If you want to match your field points to the exact weight of your broadheads you could always put the belt sander to the collars and use a grain scale, but has been said 5 grains amounts to near nothing in relativity.
I think you will see improved flight with the lighter heads. Also, did you pay attention to grain direction when you built the arrows? Back when I first started building my own wood arrows I didn't and couldn't figure out why some arrows flew better than others. I thought it was my shooting form and it nearly drove me crazy! I was fortunate enough to have someone make the observation that when I built the arrows... I was not consistent with grain direction (Thanks Dad!).
I agree with the idea that looking for perfection may also drive you crazy. The same guy that clued me in to the arrow grain situation has always said... "Strive for perfection but be happy with excellence" (Thanks again, Dad!).
OkKeith