In setting up shopping cart price rules, sometimes you don’t want one discount being used and then another being used on top of that. That is what the dropdown “Stop Further Rules Processing” is used for.
If you don’t want other rules being processed while this promotion is on, change the “Stop Further Rules Processing” dropdown from No (default) to Yes.
I’ve found often the discount rule ‘priority’ is set below that of another. A discount rule priority is basically just a numbered system from 0 to 999…. that allows you to set what discount scheme has priority over another.
So in the above case where you are running into ‘stop further rules processing’, you have to make sure these rules are set as LOWER priority; otherwise they can still work.
0 is the highest priority. So if you have your overriding rule set to 0 and everything else above that, it will stop all further rules processing. If you have it set for 1 or two and you still have other rules set at 0, these rules can still be included (unless these rules are set to sto further rules processing).
Hope that made some sense!