Using a diamond plate finer than the hone being lapped to do more than a very light lapping is not a good idea as it's very easy for the removed abrasive particles to build up thick enough to bite into the nickel plate that holds the diamonds in. When they are near the same grit or when the diamond plate is finer than the hone, the abrasive particles removed from the hone during lapping are often larger than the distance from the top of the diamonds to the nickel plating, so they can very easily dig into the nickel and remove diamonds.

Personally I've never had any diamond grit embed in any stone I've lapped with a diamond plate, but that's not to say it isn't possible. Most of the time this is much more likely with softer stones. Abrasive lapping using loose grit is based upon this fact - copper is often used as a lap due to its softness - the grit is distributed across the copper surface then embedded with a hardened steel roller or pressed in with a hardened steel block.