Ok so I been doing this quest 30+ times now and have about 12 settlements under brother hood control, heres the weird thing I had Danse with me the whole time and never lost the use of the work benches in the settlements.

That being said I send him away and do "Feeding the troops" quest solo and I lose control of the settlement. Everything I have read has said unless you murder everyone to complete you can't retain the settlement so is that a bug or what.. I wouldn't mind not having to rush around defending these places anymore tbh.

And to double check I went and reloaded before doing the quest grabbing Danse and didn't lose control of settlement, so there is something with that.

Sounds like a bug though I haven't personally encountered it. What system are you on? If you're on PC are you using any mods?

Ps4

You don't have to kill all the settlers to get the Settlements into the Brotherhood you can persuade (or Intimidate) them as well........if its working correctly you shouldn't be able to enter the workbench at all once its under Brotherhood control. If you can enter the workbench at a settlement its your settlement.

Thats what I figured, kinda nice it gives you a way to stop micro managing the settlements once you have them the way you like.

Well I figure out now (after doing these quests way too many times..) you lose ally status once you go below 50 happiness, stealing their food with persuasion drops-10 points each time.

One time the quest gave me Sanctuary Hills. That was a worry. But, after talking the guy down to 500 caps (Preston hated that, lol) it said Sanctuary was now under BoS control, but it wasn't (thankfully). I could still access the workbench.
Nordhagen, otoh, was under BoS control afterwards. I don't care for that one, though.

I don't think they go under BOS control if you simply buy the crops, so if you control the settlement before the agree to sell crops to the Brotherhood you retain control.

That's good then. With Nordhagen I used one of the charisma options, which wasn't very nice, IMO. Now I know not to do it that way again.