How does the clothes stat modifications work?

[Flo]

I have the Worker clothes, and the Sportswear clothes. But when I try to upgrade my Workers to be on par with the Sportswear, I can't, all I can do is level down the Worker clothes!

I could upgrade the Worker hat, but only to a specific other hat. I couldn't just chose the stats of every other hats I have.

So how the hell does it decide which clothes you can or can't upgrade to?

[Sarcosmic]

it doesn't seem to be super intuitive. it skips levels, seems like after becoming higher level and/or getting the next tier of clothes, you might be able to upgrade the previous tier of clothes.