With the command line tool from gmaptool you can change the map tile numbers:
gmt.exe -w -e +1000000 -m newmapsetname gmapsupp.img
So for example 93020001 will be to 94020001 and so on.
Of course you have to make sure 94020001 isn’t already in use in other mapsets 
Also the name of the new mapset must be corrected (could be done with Javawa’s Device manager as well)
Please note that overlapping maptiles can still be problematic with routing.