Replaced tires on TV, now feels like driving on ice

Is it possible, the air pressure is low and you have side wall flex?

The load range "E" tires that came on my F250, say (on the tire) max pressure is 80 PSI. The door post sticker, says tire pressure should be at 65 PSI. I have less side to side movement at 80 PSI, either with my TC or with my TT.

Every time I go in for an oil change, the grease monkeys let air out of my tires and I have to tell them to put it back at 80 PSI.