My _guess_ is that it depends upon how 'smart' the meter is trying to be.
If you have a meter that simply measures instantaneous V*I separately for each of 3 phases, then a meter 'designed' for grounded wye use will correctly meter on a high leg delta system with grounded neutral. The natural way such a meter works will automatically compensate for the phase angle and voltage differences between the two systems, because the meter doesn't actually care about them; all it cares about is the power delivered which is integrated instantaneous V*I.
A grounded neutral high leg delta is essentially a very unbalanced wye system.
But if the meter is designed with too much smarts, a meter designed for balanced wye usage might recognize and treat as an error a high leg delta system.
-Jon