Just a little query as to the wire mod on the tacho for Wasted Spark.

Since soldering the wire on the back of the tacho for the Wasted Spark, when I start the car the voltage on my secs monitor is only 11.5v until I rev past 4k once she has warmed up a bit and back to 14v plus for he rest of the journey regardless of revs there after.

Is it to do with the connections where the new wire soldered on to the big pin connection solder point is dragging the (now) more power needed to run the tacho arrow until it reaches a particular amp rate or something (i.e. the 4k revs mark) that it'll give the right voltage afterwards through-out the loom on completion sort of thing if that makes sense as that's the way I see it (not that I am electronically minded lol). Just seems strange to me. Does this happen to others who have done the wire mod.???

I have been told that it could be an extra regulator behind the dash or something like that.

Pic of the mod. I know its not the best soldering you've seen lol