Switching primers and not checking your powder weights regardless of what the bushing chart says can be very dangerous. Those are pretty low pressure loads like you said but with it being hot and dry the air is less dense and you might get some really light throws the will leave a wad stuck in the barrel
Henrydog, your comments are valid and well taken. In my case I bought 3K of the 3/4 oz wads and am down to somewhere around 500 now. Haven't had any issues, nor has my Hornady 366 press every had light throws. I do have a MEC 650 that has issues with light throws and have to carry a cleaning rod with me when shooting some of the ammo loaded before I figured out how to fix the problem. I had the brass washer installed upside down and the bar wouldn't cycle to the powder side all the way.
Before I load with the new jugs of powder I have I will weigh to confirm just what my powder charge is. I have finally drank the Koolade and believe the bushing charges need to be weighed rather than taking the charts word for it. There's too many horror stories out there.