Big difference in some chisel plows. Big difference in what some people do, or expect from a chisel plow.
2955 was sort of a "mid-framed" tractor from Deere's line. I had a 4250. Just one generation earlier, it was a bit larger and heavier, plus 30 more hp, and with weights and fluid in tires, probably 4000 lbs heavier, PLUS MFWD. I used a 9 shank DMI chisel plow that would just about stop the 4250 in its shadow when dropped below 10" deep. We have lots of clay here.