Premium shipping with weekend delivery

Is there anyway to get Amazon to recognize that UPS and USPS both offer Saturday and Sunday delivery and transit for packages? I do two-day premium shipping options and sometimes customers take them. But for some reason if I ship an order on Thursday with 2-day premium, Amazon tells the customer it want to arrive until Monday even though it'll arrive on Saturday. Same with Friday even though it would arrive on Sunday. And it's showing that to the customer so it's effectively turning today sales that would make it by Christmas for instance into sales that won't. Obviously at this point it's probably too late to fix it for Christmas weekend, but I'd like to have this fixed moving forward if it's fixable. I'm just kind of curious if there's a setting somewhere or if this is just Amazon being really obtuse about what counts as business days for the shipping companies. I'm pretty sure on seller fulfilled prime those days would work so the weekends would deliver, and show to the customer that they would deliver. But they don't seem to show it as a reception option for the two-day premium.