The problem is the return flights.
Based on the schedule you posted earlier, you have 2 monday, 2 thursday, 2 friday that return the same day.
You have tues, wed, sat, sun flights, but all of those actually return THE NEXT DAY. - This is the important bit. What that means is on the return flight, on Thursday and Monday, You actually have 3 flights. The two normal Thursday flights, plus the Wednesday flight which returns just after midnight on Thursday morning. You can see that in the pic swiftus posted.
That's why you're getting the oversupply warning.
*edit* And yeah, you don't have any return flights on Tuesday or Saturday. Because Tuesday's single outbound flight actually returns on Wednesday.