Full boost is about 3.2k rpm, starting at 2.5k rpm. You can see where it hits full boost on the dyno graph and the torque really jumps.
I don't think I've every tried to go from < 1K rpm in WOT. I'm not sure why I every would either. :)
You're calculations are way off, but I won't be any help with the compressor map.
'06 forged, GT3082R turbocharged, meth-fed Focus. 12.43 @ 115