[Kenwood] TS-930s and RTTY using FSK

[Barry Baker, K4CZ]

I am using my TS-930s with MMTTY software and a USB microKeyer interface and
just completed my first FSK RTTY qso.  However, when I use my narrow CW
filter in FSK mode, the receive bandwidth is not centered in MMTTY's FFT
display window.  The filter bandpass seems to be approximately 200Hz below
the midpoint of the default mark/space settings in MMTTY.  I can adjust the
MMTTY mark default to 1925Hz for receiving but I think my receive and
transmit frequencies would not be aligned.  I turned the CW VBT fully
clockwise which helps but most of the bandwidth is still below the mark
frequency.
 
I thought that I might have an incorrect setting in MTTY or the soundcard
could could be out of calibration but another op suggested that the 930's
BFO oscillator (shift) is probably out of calibration in FSK mode.  I just
had the 930 aligned and the filter seems fine in CW so I'm not sure if that
is the problem.  Does anyone have any suggestions?  Also, if the FSK mode is
out of calibration, is it VR26 that needs to be adjusted?  How complicated
is the adjustment (i.e. do I need a frequency counter or can I just turn
VR26 until the bandpass is aligned in MMTTY)? 
 
Thanks and 73,
 
Barry K4CZ