I personally use the HC and KHZ sets in presets other than the HC and KHZ shell. The shell was created because the documentation suggested this as a starting point and many users requested that the shell be created for it.
As stated in the shell notes -- Note: This is not the only way to apply frequency sets from the HC or KHZ database.
With that said, the contact version was removed because the preset used an offset. For some this created issues when they either over used or ignored the body's warning signs.
HC are just sets of frequencies from Hulda Clark, while KHZ are frequencies that were raised to kilohertz range (by multiplying by 1000) from another list -- the name now eludes me.
When using a remote shell in a contact mode, many considerations should be taken such as Amplitude Ramp, Reduce Amplitude, Swap Waveform, Offset, and Amplitude. Many of these settings are not enabled or adjusted correctly in a remote preset.
Advise that if you wish to use sets from HC or KHZ in a contact method, that you use a current contact shell until you are familiar enough with the system to adapt them further.
For more details, please check the link: