Glenn, the B&G manuals tell you can adjust MHU windspeed - but also that it is factory set and not to do so.  The possibilities I can think of are:
a) The downwash tables (which discount airflow over the top of the rig) are over-adjusted;
b) The mast height is configured incorrectly
c) The wand processor is reading incorrectly
d) There is something else wrong in the calculation between MWS and TWS/AWS - look in the manual for the TWS diagram.
The first thing to do is figure out if the wand processor is under-reading.  TWS is notoriously difficult to estimate.  A crude way to do this at the CYC - I think you are there - is find a TP close to you that is live, take your tablet to that boat all fired up, and do a visual on comparative AWS and TWS.  The two boats should be close enough to be in the same microclimate.  I have also done this by comparing logfiles if another boat is racing close to you for a while .. but that involves "you show me yours and I'll show you mine" about which not all are keen.
If there is an obvious difference, check the above config tables first.  If it isn't software related, dismount the wand and get it bench tested by your favourite marine electronics guys - but getting that done between now and 26th December will be a stretch.
I'll be down there Saturday arvo doing calibrations, PM me for a discussion if needed.