I think there is one other mistake:
"Lamps sensitive to mains variation": It are not lamps, what are sensitive, but their ballasts. On regulated ballast they would be fine as well, same as e.g. MV. The problem is, ten the cheapest regulated ballasts is a form of constant current source, what is fine with MV's, but make the HPS thermally unstable. However the "Mag-Reg" ballast style would be fine, as this type decouple the load characteristics from the line regulation property.
And these days electronic ballasts do the regulation job even better, however are more expensive (and i do not mean those cheap LOA-like high frequency lamp killers) and quite sensitive (overvoltage spikes, temperature)
While reading it I recall
your warning at LG that one should never use HF electronic ballasts for MV lamps.
So those ballasts you speak about here are low frequency ones (what frequency?), I suppose.
Am I right they could be used also for MV lamps (provided OCV and current parameters are correct and ignitor turned off)?
The only reason why they don't exist is the fact that when electronic ballasts appeared, MV lamps had already been almost phased out, too rare to bother with developing electronic ballasts for them?
