Can I help youspeaks for us all. Strictly speaking the boys are not even supposed to serve without jackets which is the most stupid thing going. As far as I am concerned, as long as the crew member is wearing his name that is all that matters.
There is just no pleasing everyone. I have noticed over the years that this tends to be ethnic, - Some groups prefer it cool, but please remember that not everyone wants to sleep, and that if it is cool - some people are distinctly chilly. Elderly people feel the cold particularly. Actually I always set it a degree lower than we are supposed as that seems to generate less complaints.
I cannot speak for CIHY but I have been driven crackers by the 777 before now as it will vary so much within bits of the cabin though it does seem to be better now.
I am going out on a limb here, but I wonder if there have been any studies effect of cabin temperature on DVTs?