Borgelt B500

I would be interested to hear from users of the B500,
especially those in Europe and those with the GCD2
with mini-sd card.
I bought my unit at the end of last year, I find the
steering to a waypoint information is consistently
7-14 degrees out. The manufacturer is unable to reproduce
the problem and tells me he has had no other complaints.
As he is in Australia I suspect that the problem may
be to do with the longitudes and latitudes which I
fly in, I have seen the problem in both the UK and
Germany. He tells me that the software is the same
for users with the old GCD without SD card. I compare
the course with a Garmin G3P, a Volkslogger and most
surprisingly a PDA running mobile SeeYou from the datastream
provided by the B500. The other 3 devices agree within
a degree but the B500 usually shows turn 10 degrees
left.