Kerbal Space Program

The built-in decoupling function of the Engine Plates does not fit KSP
+Their mass and cost is much less than that of comparable decouplers #19026
+The delta-V calculation sometimes misses stages with engine plates #20926
+The Reset Staging and Engineer's Report functions behave wrongly with engine plates #19027
+Their decoupling function is not clear from their appearance
https://forum.kerbalspaceprogram.com/index.php?/topic/181642-why-is-the-engine-plate-a-decoupler/

The Acapella craft, built for the stock Missions, uses an explicit decoupler on the bottom node of the Engine Plate, so maybe the Engine Plate was not intended to have a built-in decoupler.

If you remove the decoupler function, making us use a separate decoupler,
@PART[EnginePlate*] {
%category = Engine // or maybe 'Structural'
-MODULE[ModuleDecouple] {} }
then a cluster of engines on an Engine Plate behaves the same way as engines: They get shrouds that appear with, and detach with, a decoupler placed below them. Then cost and mass of the part make sense, and the Staging, Engineers Report, and delta-V functions are restored to work as they do with non-M.H. parts.

If a new set of EnginePlate*_v2.cfg is made in a future version, then for backward compatibility the former *.cfg can be kept with the usual
@PART[EnginePlate_?] { %category = none}