While technically correct, X still sets the amounts, both min-max bid amounts and the amount of staterooms it deems eligible for bidding. There was a thread where someone said they had an inside, bid on a balcony, was told they won a balcony yet once they received their room number it for a royal suite; for the record many of us, myself included, were highly skeptical. However, someone chimed in who claimed they had insider knowledge and once PlusGrade completes the biddings, all they do is send X over a spreadsheet, X employees still have to change the cabins in their reservation system and therefore mistakes aren't unheard of. No idea if either of those claims were true.
My WAG (Wild A$$ Guess) is that X can see the bid metrics at any time. Based on the very limited sample of datapoints, the conclusion (which may change later with more datapoints) is that those who bid either the minimum or perhaps near minimum will receive an increase your bid email if they're expected to lose. I do know that it isn't uncommon for the bid minimums to increase the closer you get to sail date which my WAG is because there's now less staterooms in that category available.