Can this be adjusted? It's good to put a warning in there, informing people this may cause considerable delay to their tx, but for users who know what they're doing it would be great to at least have the possibility.
No I don't think mycelium lets you decide custom fee settings for yourself. Some of us discussed it, but nobody found a way to adjust the fee low priority pays, or the fee any other priority pays. Mycelium decides for you.
I agree there should at least be a warning about it, and consider allowing users to set their own custom fee is an essential feature for a wallet in today's overloaded network.
There's a few thread's discussing it. This is the latest one.
https://bitcointalk.org/index.php?topic=1741328.0