bearisgray,
i don't think you're cutting wider - imo, we lose those few threads that make that difference in the cuttting through no fault of our own. i think it's just the width of the scissors blade itself. what we really need is 6 "generous" inches to start with. do you think? i make up the difference with scant, really scant, seam allowances. i don't know what else to do. but it makes me nervous.
i agree with you about the strange shapes that you can end up with when you buy pre-cuts. that's one of the reasons i don't care for them.