If i BRT my attack more than once can Evil Plans respond to the multiple BRT's effect or would i have to Evil Plans for each individual BRT? Would i have to have an Evil Plans per BRT or can i respond to the multiple BRT's.

evil plans responds to a single instance of a check being modified for the purposes of the damage boost, but the check will be returned all the way back to what it started as.

so say your attack gets BRT'd twice for -4 and -5...

when you make the check, you resolve the check modifications one at a time. you check a 5cc. you resolve the -4 first, then you resolve the -5. respond with Evil Plans to the -5 being applied, giving the attack +5 damage, and the check is returned to the initial 5cc.