LEM
In China many OM's are at 800' (PEK is an example). It may be a bit late to verify if u r on the correct lobe.
I think the old dme/alt gross error check (say at 10 dme ) is the ball park check for lobe (or say 6 dme and 1800') and the OM verifies the G/S more accurately wherever the OM may be.
I think a bit of common sense needs to be applied here.
(prepares to get shot down.......)
gliderboy