When stretching and folding dough and it gets tight, is that time to let it rest?

When I make my sourdough, a rested dough will stretch and fold 3-4 times before quite suddenly going tight. At this point it's likely to tear if I stretch much more. Should I put it down and rest it again, keeping stretching with some tearing, keep stretching but more gently, or what?

My typical loaf is a 50% wholemeal seeded* sourdough. I'm not going for the very open crumb found in many white sourdoughs, but more of a tasty sandwich loaf - I also bake it in a tin. But it's perhaps a little dense. It's initially kneaded in my stand mixer at 59% hydration, then after 30-60 minutes I add the seeds, salt and more water bringing it up to 65-70% (hard to judge exactly because I soak the seeds and they bring some water with them). Once the dough comes together again in the mixer, which normally involves some resting, I stop it and let it rest. Then I stretch and folding every half hour or so until bedtime (a variable number of times depending on when I started). After the last stretch I roughly shape it and put it in a loaf tin, pressing it into the corners. The tearing happens preferentially at the seeds but can occur anywhere. This routine works with my evenings, and is adapted from the recipe I got with the starter.

*_{about 9% (baker's percentage) seeds - sunflower, pumpkin, linseed etc. in variable proportions depending on where I've been shopping.}