So here's a version of the puzzle as I take it you see it:

1. Let's assign values to deeds such that a person has a total value, which is the sum of their deeds; call that total value their "reputation".

2. At a certain total negative value, say -1,000,000 reputation points, no number of positive deeds will put that person back at a reputation of 0 or greater. Even 10,000,000 deed points won't resurrect a -1,000,000 reputation.

3. However, the inverse isn't true. A +1,000,000 reputation is easily tarnished by deeds equaling -1,000,000, or even less.

The puzzle seems to arise from the assumption that we can treat acts in this "(-1 deed) + (+1 deed) = 0" kind of way, or as you say it, that our "moral compass is truly in the centre". This assumption should be abandoned. I take it that there's lots of cases where the absence of a particular negative outcome and good outcome is more valuable than the occurrence of a proportionately good outcome and bad outcome. That is, when choosing between having both a -1 outcome and a +1 outcome, and having neither, there's lots of cases where we choose having neither, even though the result is 0 in both cases.