it is not the idea of abstractions to store
stuff inside them.
do not forget that a patch could call two
instances of the abstraction patcher.

what might be the right solution for you is
adding arguments to your abstractions.
that means use [#1 i] and [#2 f] instead of
numboxes and connect a loadbang to them.

later when called as abstraction the
arguments can be initialized from inside,
or by giving the abstraction object box s
arguments, and can be set by inlets.

when you want to store "last use values"
you can now that from outside much easier
than with numboxes.