Coiling shouldn't have any effect, since it is cable and not a wire. Coiling single wire increases inductance, but coiling wire and return doesn't - because both wires in cable create canceling magnetic fluxes (opposite direction of the current). Non-inductive wirewound resistors are created by folding wire in two and winding pair of wires with ends on one side (bifilar winding). Winding wire and its return also creates "common mode choke", that has inductance for common mode signals and no inductance for normal (differential) mode signals. Coiling power cable, especially on the core, creates such common mode choke filtering out electrical noise induced in both wires with no effect on regular (differential) operation.
