Really dry grass on a slope is also more slippy than "medium" grass (and then goes slippery again when it's wet). When I was using a ZT, I learned to use the downhill wheel to do most of the work when turning around, going across a slope (and also doing it a bit slower). I would use turn so the front goes uphill, then backwards turning so the other wheel is downhill and you are just below the previous pass, and then off to do the next pass.