On March 14th there were a number of fixes and changes made to the game as you all know. Having played 200+ hours before the update I notice the slightest of changes with the game. That being said the changes in the pc updates post http://community.callofduty.com/message/414210154#414210154 does not seem to contain all the updates that were made. From the 14th to the 16th there was a noticeable change in the way that either packets were being handled or in the lag compensation/bullet detection, so much so it made the game nearly unplayable. Yesterday (March 17), there was a noticeable improvement to these issues but remnants of the problems still remained.
I feel it nessasary to point this out because of the crud that the PC community has had to put up with since after COD4, including but not limited to delayed or zero support. During the release of Black Ops 2 the game had it's issues that seemed to be sorted out fairly quickly. The game had great balance and average lag compensation (for a cod game) and every change made to the game did not upset the balance nor lag compensation until the March 14th update.
Maybe I'm not the only one that feels like the issues and fixes that were on the console side made a b-line to PC without any thought of how diffrently it would effect PC players. I would vary much like to enjoy this game and issues like this just make me feel like PC games are getting the red headed step child treatment that they definitly do not deserve.
Sounds to me like you were always on the good side of lag comp before the patch and now you are getting what most of us were getting before then.
My game has basically been so much better since that update but there are still issues with it.
My ping in every game apart from every COD game after COD 4 is always in the region of 10ms to 25ms, but in Black Op's 2 my ping is on average 50ms to 90ms.
I can go from Black Op's 2 having a ping of 60ms and jump in to a game of Battlefield 2 or Battlefield 3 and find my ping is a low 25ms.