It's a philosophical question:
When does a comment become a comment?
Surely it is a comment when it is conceived in the mind, but then no one can record that time table accurately.
The best we have to go with is the written comment and when it was published through the blockchain.
Since I am checking the comment at #51 then I will double check the time each comment was completed regardless of when that comment was conceived. That means any edits should be considered entered at the time of the most recent edit.
Ah, but then I could flip-flop my comment # with someone else's, by waiting until they comment after me, then editing my comment to be after theirs.
What a tangled web we weave ...
The other way we could play it is consider all edits as invalid.
I made a little amendment that will work even though there is still a tiny loophole. I will check the comments at one time when I see 51 valid comments. I will record the time the comments are checked.