No worries :) Yeah, basically, since you have more SP, your reputation would not be affected. However, he would effectively be canceling out most of your SP with his flag, so while your upvote will keep you from losing reputation, you won't get hardly any monetary value out of it (1505 SP - 1500 SP = effectively a 5 SP upvote), or at least that's the theory. I may be off on the money bit, but I'm confident in the reputation part.