It shouldn't be a problem, unless the second number in the ACS_Execute or ACS_LockedExecute (0, 0, 0, 0, 0) command is anything other than 0 (it usually is). If it's 0, then the script will run for that particular map, regardless of what number it is.
As for different maps using the same variables, that should be no trouble at all. In fact, the 'world int' command is made specifically so that variables can be made to extend beyond the map and affect other maps as well. You don't see this very often in hubs, and never in single map games.