Splitting car rental

[Jimham4]

We are coming into MCO on a Thursday with a dance group that will be competing at ESPN until Monday. My wife and I are staying over a couple of days after before driving down to Port Everglades to take a cruise. Originally I booked a car with Budget for just the Tuesday through Saturday picking up at DTD and dropping off at the port. Looking to modify the booking to start on the Thursday we come in with a pickup at MCO my rate jumps from $172 with fees to over $400 with fees. HOWEVER, if I book MCO to DTD returning the car on the first Saturday and then immediately renting another car for a week to go DTD to the port the combined costs of the two rentals is only $300 including fees. Does anyone know why it would break down this way and is there maybe a better combination of days to do the switch on (weekend vs weekday, etc.)? Does the rental company care if I do a return and re-rent?