Misinterpreting C2M signed distances ?

[daniel]

Yes, you can rename the scalar fields between various runs of the M3C2 plugin (so that they are not overwritten).

Else if you really have multiple clouds (with the same point positions?) then you can also use the tool 'interpolate SF from another entity'. But mind that you will also have to rename the SFs first so that they are not overwritten.

And last, you can create a custom absolute color scale (with the Color Scale Manager - see the wiki) and apply it to all the SFs.