You are missing a very important point here. SB alters shots. Your player could finish a game with 0 blks, but hold his opponent to 0-10 shots. The number of blocked shots isn't that important, it's the defensive benifit which counts. I have two bigs with a shot blocking ratio of 35%.
The first one has 5% shooting foul, 30% altered shots and 30% failed actions --> the opponent scored.
The second one has 0% shooting fouls, 53% altered shots and only 12% failed actions. You see, they have the same % of blocked shots but different impacts on my defense.
In this example, are the procentages of all cases where the particular player has tried to defend a shot (can be seen in the play-by-play as "somebody shoots...with your player defending closely" or other comment of that sort)? And then simply judging by the result like this: scored-->failed action, miss with no block--> altered shot, miss with block-->blocked, foul-->shooting foul. Or did I get it all wrong?