Whenever you post it is usually gold. Are you able to expand on this a little?
I'm not sure on the exact stats of the HM120mm before WFA, but I'm very confident it was highly inaccurate both when attack-grounding and barraging, much more so than the GR34 81mm and the PM82mm.
Currently, though, it has a scatter angle/distance of 10/8 for default fire and 8/8 for barrage. This, coupled with a splash radius of 6, means it's very rare for the AOE not to damage a squad member with every shot (if I am interpreting the statistics correctly- correct me if I am wrong).
Compare this to the Ostheer mortar, which has a scatter angle/distance of 10/8 and 9/7, and the normal soviet mortar at 8/8 and 8/6, both with a splash radius of 4. The difference in accuracy is actually now quite a lot less significant than I'm sure it used to be.
Or you could ignore the stats, which are pretty pointless, and test it against the AI- firing at max range with vision it's quite easy to tell it's been changed and a heck of a lot more accurate.