The accuracy of 1000lb bombs released from Tornado twin store carriers was worse than when the bombs were directly mounted on the pylon. This was because the carriers twisted slightly as each bomb came off (they didn't come off simultaneously, to avoid collisions) and the twist meant that the bombs diverged left and right of the mean line. It was eventually judged that 5 more-accurate bombs were better than 8 less-accurate bombs once all the tradeoffs in aircraft performance, etc, were considered.
8 x BL755 could be carried and these suffered less from the aiming inaccuracies. As for digital TSCs for Paveway IV, these never got beyond the "wouldn't it be nice if..." stage as far as I'm aware. They really would be great though, wouldn't they!