Air exchange vs Humidity

Did you just figure that out?

Your understanding of relative humidity is no better than your understanding of gravity or the shape of the earth

Is your tent exhausting outdoors or into its room? If it’s exhausting into the room it’s it’s just recirculating what’s there. You gotta duct it outside if it’s part of your humidity control

Yeah so its winter here, garage is still pretty well insulated and part of the house ive got an mini split AC in there and I've even installed foam inserts in roller door fresh air is pulled through slight gaps from outside.
I guess I just had it in my head to keep below 50% during flower to prevent mould. After having a read, my new approach is to follow the humidity around with the temp to give the best vpd for growth stage and leave the dehumidifiers off all together which is so much easier to do. vpd also went from 0.96 - 1.12Kpa just turning temp up 2 degrees might go 1 more yet. Wait until the wife sees the electricity bill, she's in the lounge room freezing her tits off as well and plants are kicking back warm as toast.

Could you vent the hot air back into your house? That’s what I’ve done in the past for the winter and it worked out well. As far as vpd, I try to keep mine from 1.2 to 1.6 in late flower. I don’t think you will run into any problems in this range, it’s the temp swing at lights off that you need to worry about. 30 minutes before lights out my defumidifiers and ac go into dry mode.