I have not seen any 70 hour regen cycles reported on this tractor forum. Most tractors seem to be in the 25 to 45 hour regen cycles. Its certainly possible that larger tractors have longer regen periods.
Its also very possible you have had automatic regens occur and you were not aware of the fact. My regens occur about every 28 hours, but when they do occur, they last about 10 minutes. I know of several instances, while working with my tractor, I had the typical Sulphur smell of a regen and when I looked at the dash, I saw the regen light was already on. Had I not detected the odor, I would have missed knowing the regen cycle occurred.
How you operate certainly varies the regen cycle. Theorectically, the lower your working engine rpm, the faster you fill the DPF with diesel soot, the shorter and more frequent your regen cycle.