Normally a scoring relay on a GTB EM will have the 2-piece (fast-response) lock-in switch when that relay can be triggered by a playfield switch with a very short dwell (make) time.

It looks like all of the "plain" 500 point scoring on this playfield is via rollover switches, so it may be that GTB determined that the fast-response lock-in switch was not needed for the D relay. Rollover switches typically have a fairly long dwell time compared to stand-up targets or drop target score switches.

Since the E relay is triggered by drop target score switches, it makes sense that the E relay needs to have the fast-response (2-piece) lock-in switch on it.

If your game never misses a "plain" 500 point scoring event (that is, 500 points without the bonus add), then there really is no issue to be addressed. If you are sometimes missing plain 500 point scoring events, then you probably want to adjust your rollover switch gaps. If that doesn't fix the issue, there is no harm in upgrading your D relay to use a fast-response lock-in switch.

- TimMe