Disney Ticket Question?

NO! YOU CANNOT DO THAT!!!! (Sorry, just making it loud and clear.) If you try to double up and use up an extra day, your ticket will not work. When you put it into the machine, the machine will spit it back out and state that you had already been in the park that day. Also, they cannot and will not be able to override the system. Your best bet is to buy a 3 day, one park per day ticket and a one day park hopper.