Depends on how long the outage was. Score is an exp function so your earning degrade to 0. I'm not sure how long it takes. I have been thinking listing the shares on the stats page isn't the best metric. Have score and total score would be better since those are what your earnings are actually calculated on.
I know why the functions are there, but its effects do seem a little harsh. Maybe it could be reduced a little? Otherwise those with massive rigs could switch do the opposite of the normal problem, run them on a PPS pool, then they notice its been 45 minutes here switch.
You can't predict the end of a round, and you can't mine the end of a round and expect more coins than normal.
The only way you can earn more than expected is by mining the first few minutes of a round and then mine else where. On average that will earn you a bit more than PPS.