My 59 plate E350 231bhp also shows wonky DPF settings on the iCarSoft MB2.0 - 89,000km since last DPF regency etc. Was driving me bonkers - I even took it to Mercedes Brooklands and another indie as I was sure there was something wrong with my car, but nope, no issues with the DPF or any sensors. I contacted iCarSoft and they confirmed that that engine isn't supported for accurate DPF readings.
My 60 plate E350 265bhp has no such issues with MB2.0, readings are accurate.
Ignore those figures. There's no way your car is running and hasn't regenerated the DPF in tens of thousands of miles.
It may have been fixed in firmware updates from iCarSoft, but you need a Windows PC to do the update (I don't have one) and their support is a bit of a nightmare to deal with.