I assume the wine is clear now? Or at least reasonably? The reason I ask is I usually don't add finings until after the wine stops throwing lees on its own, then clarify. This usually requires several rackings, and topping off is very common at each racking.
I'd top off now, and consider when to fine later on. You can fine it now if you want, of course, and then rack it off on the lees in a couple of weeks.
Edit- I just read more carefully and see that you've already fined this. That's fine, but you top off at EVERY racking! So top off now, and when you rack it off of the sediment in a couple of weeks, top it off again!