I´m not sure about that. Have you documents to prove that there is a floor that can be not be crossed and if so what it is and why, in best case with sources? Or ist just another of your assumption poured in fact? Maybe @James has thoughts about this?

Personally i think there is not to much way from the 860W lamp to a 1000w and i think the limiting factor ould be a lak of demand rather then a lack of possibility, as these big CMH lamps are more expensive to manufacture then QMH and have different optical characteristics..

This is more likely.

 I Agree ! Going up by only 120w can't be that difficult...Or at least I wouldn't think !  @James ?