As far as I know , I haven't seen a change in the stats page since Oz migrated to the new server,correct me if I'm wrong,but is it that the stats page was not modified to track the new server IP address perhaps?
I'll give you an example my own stats I was ranked 1853? but that was before server migration, and last time I checked,I am still same rank.
So I look at this as an opportunity to practice on different weapons because dying a lot more to gain proficiency does not appear to have an impact on current rank.
But I empathize for the players who already have those proficiency's who are not getting due recognition for their in game skills though.