Back EMF I've heard of.
Counter EMF is new to me.
I'd prefer to name it impedance.
Unless you've got ultra special bench test gear -- 0.15A is within the tollerance for error on every piece of field test equipment I've touched.
As for track lighting issues: IMHO they all have touchy joints/ connections.
The actual conductors are thin rails of copper -- sometimes tinned -- but definately not designed for really heavy loads.
Which is to say, that they can mount more loads than their intrinsic bus can carry -- without heating up to a fine glow.
Also, I've run into ancient age resistance style voltage controls/ dimmers that make everything worse -- much worse.
Good luck.
