I had a quick look at your roster, nice job so far by the way.
I was just going to mention that because you are updating the 2012 stats before you go any further with those you may want leave the stats1 column empty and add 2012 to the stats2 column. This would involve moving all stats over one column to make room for them.
What is happening is if you fill the stats1 column is after simming one season all actual 2012 stats you've entered will disappear. If you place the 2012 stats in the stats2 column then after simming one season they are still there, the only thing is you are going to see two 2012 stats listed (one real and the other from your simmed season), that has to do of course with the fact we can't change the start of the season to 2013.
If you check all 2k rosters leave the stats1 column empty.
I'm not sure how you are gathering the stats for 2012 but one way you could do it is to open the xbox 2k13 roster I have in the schedule thread and just copy and paste those into yours. Here it is in case your interested. Roster.rar