They consistently have added credit back into the trips because the optimizer only deals with math. That math maxes duty time and minimizes layover time while not allowing credit. They haven't even tried to set length parameters, who knows if that would result in just a fraction more credit and less back end cost. As someone who would prefer to never sleep in another hotel hammock, day trips are the right answers. The facts are that since the pre-month optimizer the trips have been more fatiguing. And the operations optimizer and human factors destroy the savings as soon as the month begins. There is a better way but your expectation for unadulterated efficiency is a theoretical goal that never meets reality. They have already proven they are willing to tweak. Pilot QOL was much better when the puzzle pieces of the monthly line were more various, but we know that's not the company goal. But QOL still happens as broken trips are gobbled up by necessity of the not so rare (anymore) PCS/swap board ninjas. The company can either have efficiency or reliability but not both. The profitability of Delta was built on reliability.