Another starting problem

You are leading yourself down the wrong path with your test procedure, because the two circuits feed back into each other. When the key is in "run" the power goes from IGN1 "run" through the ballast and to the coil. AT THE COIL + terminal, the IGN2 is essentially "that point" electrically. So the IGN2 line back to the ignition switch "sees" the run voltage AND THAT CHANGES some because of the load on the coil through the ballast, and because of the charging voltage. "Running," coil + will vary somewhere between 10-12V when the system is running at nominal 14V With key "in run" but engine stopped, it will be somewhere from 5-8 or maybe 10V, because the battery is down around 12

IN START the IGN2 is "supposed" to be "same as battery." That is, if when cranking, the starter pulls the battery down to 11V, then IGN2 should be about 11. This will show at coil+ AND THAT NOW will feed "backwards" through the BALLAST and show up on the IGN1 line. There may be loads on the IGN1 line which will pull the ballast "down" and so on the "key" side of the ballast, that voltage will / might be quite low

ON NEWER CARS with factory breakerless ignition, THIS BACKFEED from IGN2 (in start) --through the ballast "back" towards IGN1 NOW IS THE STARTING POWER SOURCE FOR THE electronic ignition box!!! IT MUST BE there or the box will not operate in "start."