UPS Simple Rate - Shipping Options

Hi trying to utilize the UPS Simple Rate option, and the website specifically mentions "5 Shipping Options - next-day, second-day, three business days or five-day delivery".

However, when I am trying to ship my item, I am not getting the Next Day option, the fastest is Second Day. Does anyone know if Next Day shipping in Simple Rate is only available within a certain distance or to a commercial address or something?

And for anyone else who finds this post later:

• Yes, UPS still does Flat Rate (Simple Rate) as of June 2026
• You select from 5 box sizes (sized via cubic inches), and there is a single rate to ship
• You can use your own box, as long as the volume fits under their prescribed ranges
• Package must weigh less than $50
• This can only be done online, and it's tricky to make the online calculator do it. You have to choose "Go to Previous Experience" in the shipping window, and then an option appears to toggle on "Use Simple Rate Packaging"