This is weird, that’s what I would call a much better cable than the - probably unscreened - telephone cable, and very close to what I’ve used in the past.
If the telephone cable gives you 27 W of noise/pickup, I’d go with it.
In emonhub.conf - the “scales = …” line does apply a multiplier to the input, e.g. Vrms is multiplier by 100 inside the front end, sent as an integer and multiplied by 0.01 in emonHub to put it right again. The 6 temperatures are similarly multiplied by 10.