Replay levels relate to the score at which a replay/credit if on site or user adjustable to say extra ball and how many replay levels or scores are available per game.
You can change the number of replays your machine has and at what scores they happen.
+1
if you set it to 1 then you will only get 1 score awarded replay or extra ball (depending on if you have "replay awards credit" or "replay awards extra ball") per game. if it is set to 2 then you will get 2 score awarded replays or extra balls. (one at the first replay score and the other at the second replay score and so on.)
