^^^ Actually the 19T compressor wheel is operating at ~70% efficiency under the conditions shown in the datalog above (PR~3.0 @ 450CFM). The problem is in the small hotside.
The only reason the turbo can maintain 20 psi to redline is greatly reduced VE. In order to maintain the flat boost profile shown in the datalog, it was necessary to ramp up WGDC (and therefore EGBP) with rpm. As a result of the higher EGBP, the air flow through the engine is reduced (at a given intake manifold pressure). The lower airflow through the engine allows the turbo to maintain high boost.
The end result (lower MAF through the engine)is no different. However, the above data was collected to characterize the performance of a clipped and ported TD04-19T at operating limits. It's important to evaluate data posted in this thread within the context in which it is given. Obviously running the turbo under these conditions is not recommended.