My FR945 is getting a wrong altitude consistently, which is 60-90m higher than actual. I tried to solve it by calibrating the altimeter and barometer before an activity, it was okay at the initial 30 seconds, but it goes wrong again once it acquired the GPS lock.
I believe the FR945 can do a decent job on the altimeter once it correct this issue, because the pattern is very consistent by 60-90m higher than actual.