There are many misconceptions still current about cabin heating and cooling and general airflow. Long ago, in the dim and distant past on the Classic 747, when pax loads were below a certain figure, it was normal practice to turn one of the three airconditioning & pressurisation packs off as the air demand was lower and they cost monsy to operate (drawing high pressure bleed air from the engines causing slight loss of efficiency). This has never been the practice on the 747-400, and I'm fairly certain nobody does this anymore.
As far as temperature control goes, don't even start enquiring about economy with hot/cold cabins. None of the crew are interested in whatever academic connection you think you may make. The crew actually want to be comfortable as well as they do vastly more hours in that aeroplane than you!
Many aeroplanes have command of cabin temperature on the flight deck. People set normal temperature positions and leave it for feedback from the cabin crew to adjust. Cabin temperature indicators are quite untrustworthy as they can get clogged up with fuzz- they rely on moving air for temperature measurement. Many aeroplanes have temperature controls in the cabin for cabin crew use. There is the rub. That cabin crew may have been working frantically in the galleys in front of hot ovens and getting hot meals out into trolleys. Not surprisingly, they feel hot. So they turn down the air temp! If they are not doing hot meals and are hanging around, if they feel cold, up it goes. Now this bit is controversial and only for MCPs like me. Like all women have trouble reversing and cannot work out which way to turn the wheel, have you observed women operating temperature controls on heating systems at home/office? They never tweak it- they tend to rotate almost fully up or down. My old fashioned view is to keep women away from temperature control systems!