The plug in machine readings......
Couple of things puzzling me. You say your van is losing power occasionally. He's diagnosed clogged DPF i assume, due to these readings. He'll be able to tell if its full of soot etc... based on the readings. The DPF should be able to regenerate and clean itself. But for whatever reason it hasn't . It is easily possible to remove them and have them cleaned. But he's jumped ahead..,.suspecting, even as chance that this may not work and you could remove it ?
He doesn't sound confident at all to me.
As someone else has just mentioned, the law around DPF's and emmisions is changing and getting tighter. Removing a DPF, even in software could be a costly mistake to make. And probably uneccesary too.
I'd be going to someone who specializes in DPF's.