Hi Pete.
If the EGR was disconnected or blocked the air mass should be higher not lower.
Look at your boost pressure @2500 RPM. I would expect to see a much higher figure like 200 KPA which would corespond to around 900mg/stroke.
You could be onto something with turbo/ exhaust blocked. I would also bechecking for boost leaks and turbo control.
MAF calc is a very good app for working out air mass on engines.
HTH Fiachra.