Wow good example of munipulating stats through math. First of all what does attempts have to do with fumbles, he cant fumble during run plays as well? 11 or more fumbles since Wiz has been here, period, end of story. In a per game situation sure he got better from 2007 to 2008 but then again he got worse from 2008 to 2009 so was it every actually fixed or just a anomoly?
But if you want to play the attempts game here we go
2007 - 451 attempts - 29 int's/fumbles = dropping the ball every 15.55 attempts
2008 - 598 attempts - 25 int's/fumbles = dropping the ball every 23.92 attempts
2009 - 513 attempts - 25 int's/fumbles = dropping the ball every 20.52 attempts
So he gets better then gets worse again. I can play with stats as well to make my point so it all comes down to one thing, Warners Fumbling issues were lengendary until the day he retired for a reason and it wasnt just to pick on the guy it was because that is what every DC in the league tried to capitalize on because they knew it was a weakness and every analyst knew was a problem his whole career, it never got better. I wont even go into comparing the Green years to the Wiz years considering Warner was still having issue's with hand strength from his NYG days so his slight 1% better as you put it could just as easily be from something other then QB coaching things such as better OL play compared to Green, gloves, not playing from behind as much taing fewer risks, and so on.
Double digit fumbles a year is crap no matter how you slice it or want to play with percentages and it was never fixed by Warner or the coaches, end of story.