You never get -2 for the up-vote. But you might get a down-vote, though I do not believe this was what happened in your case.
But for completeness, the issue is this: at 200 points via votes you are capped, as I think you know, and upvotes after that do not count.
If you then get a downvote you drop to 198, even if you have plenty surplus votes, the earlier surplus downvotes do not compensate this.
However, if you get a another upvoote after the downvote it will count again.
See this answer Why do the up-votes after reaching daily rep cap not contribute to compensate the subsequent down-votes?
Regarding why some seem to have a higher cap, this is due to the fact, as explained by Daniel, that not all points one can gain are capped, points from acceptance and bounties are exempt from the repcap.
Thus if you have 20 upvotes and two accepts, you'd get 230 for example (ignoring other events).
What you precisely saw is hard to tell, but it could be explained by the fact that you deleted an answer too. This influences your score as all votes from it are discarded, yet this might not update instantly. When the delete of this answer kicks in, you gain 2 points, but in turn the value assigned to your last vote would decrease, as it now only took 2 to get too 200, not 4 as when that answer was around.