You could use a field coded as:
{=MOD({={PAGE}-1},2)*INT({PAGE}/2) \# 0'A';;}
You can use this next to the existing field, or on its own on the even page with a 'different odd and even' page setup.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]

Hi Paul!
I have the same idea as Anthony had: numbering every second page with consecutive numbers, aka foliating.
I tried both of your formula, however neither has worked: my ms word comes with syntactical error message.
Unfortunately I did not find any useful information about programming field codes (e.g. none of the sources know the function(?) mod() and int() outside of excel and noone mentions the modificator \#, but \* only.)
So, I'd like to ask your kind help to update your formula to the need of Word 2021.
Thanks!
Greg