Using UMIK-2 mic with calibration file-measured value 3dB less than expected

[János Zöldi-Kovács]

Hi!
I've a UMIK-2 microphone. I'm using a modified calibration file (to the same format as Dayton IMM-6 uses). I've imported and loaded; It was successful (the 1/3 octave calibration shows the values imported).
Unfortunately using a Bruel microphone calibrator it measures exactly 91dB instead of 84dB SPL. The same mic and calibrator shows 94dB with REW's SPL meter. Using a TES1351 sound level meter shows also exactly 94dB. What should be the problem?
The cal file I'm using:
*1000Hz -11.36

10.054 -5.22145
10.179 -5.1222
10.306 -5.02455
10.434 -4.92855
10.564 -4.83405
10.696 -4.7411
10.829 -4.64975
10.964 -4.5599
11.1 -4.4717
11.238 -4.3849
11.378 -4.29955
11.52 -4.21565

...

The original starts with this:

"Sens Factor =-11.36dB, AGain =18dB, SERNO: 8104655"
10.054 -5.22145
10.179 -5.1222
10.306 -5.02455
10.434 -4.92855
10.564 -4.83405
10.696 -4.7411
10.829 -4.64975
10.964 -4.5599
11.1 -4.4717