Soot mass calculated should go up and down from a top of 24 or so and down to about 5 or so when regen is done. That is for checking that regular regens are happening and about every 200 miles or so. The other is oil ash residue. This builds up until the dpf eventually has to be replaced or maybe cleaned out. You can watch the other stuff but those two are the most important. Distance from last regen and % full are also useful.