That is why you want to get the S model, you just use the notches to get within about 35° or so of level, and use the tilt ability to level the rifle. I have used this and the smooth leg model, and the S model with the notched legs is much quicker and easier to get exactly level than a non s model with the smooth legs. Also, if while getting comfortable for the shot one of the legs happen to sink in the dirt, instead of needing to readjust the leg, you simply tilt the rifle back to level, never needing to come off of shooting position.
Hunting in Wyoming plains for pronghorn, as well as high back country deer and elk hunting, I prefer the Harris 9-13 S model with notched legs and a locking lever and a rear bag, with this set up on my rifle we have taken animals out to over 900 yds. Save yourself some money and buy the caldwell swivel lock lever instead of the harris, same thing but way cheaper.
This is a good bipod, but keep in mind essentially all your shots must be from prone. If you find yourself required to shoot sitting or kneeling, you will need something else, such as a tripod front/bipod rear combo, or a tripod with hog saddle, ect. We have no problem with the 9-13 but our back country hunts we usually are shooting across canyons, so finding a good spot suitable for prone is easy enough, and prone in the desert for pronghorn has never been a challenge. If you have the extra money, get the Atlas, they are a little more steady and very strong. Not that we have had problems with the harris, but it never hurts to take some wobble out of the equation.