With all due respect, I have a completely different take on this, and I use that term often. There is a limited number of choices that apply to a game that is partially original, and sometimes in fantastic shape.
For instance, the cabinet is redone, but the playfield is in incredible original shape, or vice versa. I suppose a seller that lacks integrity could list such a machine as "fully restored," "HUO" or "shopped and fully refurbished" but sometimes none of those fit the description better than partially restored.
If someone posts a game as fully restored, I assume that every single part, including the cabinet, the boards, the mechs, switches, backglass, displays and yes playfield are COMPLETELY restored. How many machines that are listed as such truly are? I would imagine that number is pretty small.
Maybe it is a matter of looking at the glass as half empty vs half full, but I accurately and confidently mark some of my machines as partially restored, because they are. I can assure you it is not a lack of money, a half ass mentality or a desire to inflate the price of something that isn't justified. I wish there were more descriptors in the drop down menu but I usually elaborate in the text of the for sale ad and that seems to be plenty explanation to most buyers.
My tone is respectful here. I just wanted to give my interpretation and use of it. It is a shame that some sellers have tainted the term, if that is the case.