Defensive Rating for catchers

Can someone explain some of the nuisances of the catcher defensive rating. For example, if a catcher is rated 4(0) e4 T 12 ( pb-1) and the role comes up catchX, does the next dice roll create a passed ball even though his pb rating is only a "1"? Also if the guy has a low error but has a low range factor and a higher throwing error rating does he have the potential to have many more errors than the e4 would suggest? Does anyone have any insight to this information? Any help would be greatly appreciated.

The error rating does NOT include throwing errors.

For example, I have used Jorge Posada 2(-2)e1 t8 a few times. The -2 arm prevents some steal attempts, but when the attempts are made, Jorge can get those throwing errors. Below is a link to my last Posada season - 7 throwing errors.

http://onlinegames.strat-o-matic.com/te ... ng/1104610
(don't look too closely at the team, it was a poorly constructed squad that underperformed)

It is not scientific but my experience that with any kind of negative arm, my catchers tend to have up to as many throwing errors on the season as their T rating (+/- 4), those with a zero arm a tad more (more steal attempts), and those with a positive arm a bunch more than that.

Thanks that helps quite a bit.

Thanks Richard