I mow across slopes on occasion.
IMO the AT 101 bar tires are much better for traction in every way vs the crappy turf tires.
I bought a second zero turn a couple years ago. Within the first 2 hours of running it for the first time I was online ordering a set at 101 bar tires for that machine too.
I had forgotten just how bad the stock turfs are and couldn't take them any longer.