Hello. I've been playing this game for 11 years. I've known about weaving for most of my time playing and always did it. During dungeons, raids, I even got a raid trifecta with my guild a few years back. My damage was always lower than the rest of my guild but I did manage to hit a 100k parse a few years ago and always assumed things were good.
Lately, I've been meaning to come back to harder content. So I put two sets together (not bis, just tide-born and AY) and started parsing. I hadn't done a parse in like 4 years but, the first one I did, I got 115k. I thought that was good, but soon learnt that people were hitting 200k.
I looked at my cmx and my weaving was sub-optimal (0.07 - 0.11). And for the first time in 11 years I dug deeper into weaving and found out it's a different world than I'd previously imagined. I installed WeaveDelays addon and it shows most of my LAs were in the yellow, orange and red zone. Simply terrible. I kept trying and hit a 135k parse with substantial better weaving, but still not there.
What's frustrating me is that if I practice weaving skills individually, they're all in the green zone -- Perfect weaving. But the moment I start my parse a bunch of them don't register or are in the red-orange zone.

(I know, I did this in paint).
Why is this? Why can I mantain near perfect weaving like this, but the moment I start a parse I instantly miss the first 2-3, and then a few in between? And the rest isn't even green, they're mostly on the yellow-orange zone. I've tried combat metronome (and a real one!) and it seems to help with individual skills, but not in the actual parse.