Mr. Bill, thank you so much for confirming my theory.
I'm embarrassed to say 6 or 8 is on the low side... I have spent over 30 minutes on a single roll of 220 sometimes. I can do it just fine with a test roll in the light, but in the bag I find the film pops out of the grooves quite easily and I have to start over a lot. To check, I have started doing it with my eyes closed in the light, and when I feel it going wrong, looking down I see how the same problem happens in the bag. I just need to get better at protecting the film until it gets a full rotation through the reel and it settles down in the grooves. Thanks for the help!