Sorry for the really long reply. I didn't have a chance to actually try modifying the sysex settings until this week.
From what I can tell that doesn't change the setting from 0-127. It sounds like it requires multiple adjustable sysex values to get it to change but I'm not clear on how that can be set up in BC Manager. From what I've read the Matrix doesn't interpret 0 as -63 in the matrix. Are you sure it's just 0-127?