Page numbers in ms keeps

[John A.]

Does anyone have a good solution for this problem?

.KF
[...]
The current page number is \n(PN.
.KE

If the floating keep above is moved to another page, because it doesn't 
fit on the current one, then the PN (and %, for that matter) register 
holds the incorrect page.

I suspect a solution may be possible by peeking into or modifying 
s.tmac, but I thought I'd ask.

Best regards
John

P.S. There has been some discussion about this before, but no solutions 
as far as I've found:

https://lists.gnu.org/archive/html/groff/2000-04/msg00041.html
https://lists.gnu.org/archive/html/groff/2005-03/msg00015.html