[DKT1]

So now you've opened the can of worms!
The dilemma of the readings.
Is the MAF reading correctly and you have a restriction/leak in the Turbo/Intercooler pipe work?
Is the Turbo operating correctly?
Is the MAF reading incorrectly and everything else is OK, except now the injectors wont be getting the correct pulses to the corresponding RPM?
If you had a MAF that was known to be reading correctly (where you'd get one from is a mission) you could fit it and check if the readings are correct or not?
If you bought a new (Siemens) one and checked again and the reading where better it would go some way to proving the original was under reading, as long as you accept that the new one could be over reading and just as far out?
Buy, borrow or hire an air flow meter, if you can find one that will do the job, as most cheap ones are made for wind speed (mph,kph etc) not Kg/h.
you just couldn't be happy with it running OK, you had to go and tinker with it, now look what you've started