how's the layout on your 5.0? I have one close to 4x4, pin over ring finger, cg under the finger, small hole. that thing backends like nothing i've ever seen before. Most backend i ever had was a freak out, pin over the middle finger, and an xception, pin over bridge. Mass Bias balls i've drilled with the pin under the fingers have rolled HORRIBLE for me, the same reaction you're getting out of them right now. I had a hexplosion i hated also, pin in the bridge, cg swung a tad, got rid of it as i didnt like the roll. Bowling in tons drier houses this year, so i picked up another nib. Drilled it like 2x2, pin on the axis cg in towards the thumb (pics of all my stuff comming by the way, vids very possible) and it rolls AMAZING! All i can say is neither hexplosion i've seen or thrown have had a whole lot of backend. All the 5.0's i've seen thrown by anyone with revs backends a ton, in fact most people have lightly scuffed them to try and tame the backend. Just keep both shiny, though i would think the layouts probably have alot to do with the reaction.