The U360 buttons have a shift feature that eliminates the need for dedicated admin buttons if you want to save money. There are pros and cons with both options, and I don't think either one is better than the other.
My opinion: If you have 7 dedicated action buttons per player and you want a separate coin door and start button, you'll probably want to go with an encoder (e.g. minipac). Shifting for "coin" or "start" is a pain.
I see you already came to that conclusion, though. Just wanted to add something to it nonetheless.