I would try installing directly on my postwar ZW but the terminal spacing is different.
OK, so that is the difference. I've never had the 14002 in hand, did not know that.
There is no DC component in the ZW except for the offset in conventional mode with the whistle/bell activation on A & D.
I know the 14077 works with PM-1 PowerMasters and modern phase-modulated transformers, as I have done what you are doing and used the meter as a stand-alone, so there is no reason the 14002 needs to be different in this manner.
Just to be sure this is not an issue, you are aware that the 4 "U" posts on the meter are not really "common" anymore once connected? They will act like common, but if connected to a common ground layout, all four, they will each display 25% of the total current draw from the connected transformer(s). If you connect just one "U" to the layout, it will display total amperage in just the one display window corresponding to the (A-B-C-D) post below it.