This is a KD.exe issue then, the added CPU on top of the KD process is from the apps, but if that's the work of cmd.exe which initializes KD.exe, then KD is to blame. WinDbg is also a command line utility for debugging. I'm curious, can you try WinDbg or is WinDbg not supported by these apps? In relation to KD.exe and WinDbg.exe I'd like to see which has a lower processor usage consumption out of the two.
It could even determine whether to ditch KD altogether.. Or leave the option, but inform users of the differences and advantages..