It’s actually after the 10 minute window (there’s a 10 minute “cooldown” period to allow for cooler heads to prevail). I don’t know the answer to this, I’ll have to investigate.
I do know that if mods disagree with the flag (i.e., if someone tries to flag nefariously or use flags to win arguments, etc.), those flags do NOT count towards anything (except demoting the flagging power of the user who did the malicious flagging in the first place).
Yes - it’s based on flagged posts, not flags themselves, so if those posts are over 100 days old, they no longer apply.