OK, I used to be a PPG rep and 2 things that PPG had going for it with the DBC (Deltron) and Global line was good coverage and good color match (providing the right variant was chosen). I live in Canada and we have VOC laws that for the past 2 years we have not been able to purchase Deltron or Global because of these products not meeting VOC regulations, everything up here is now Envirobase (water born) or VOC compliant Omni. I can't see PPG reducing VOC's and not allowing good coverage. The only non water borne that PPG offers in Canada is VOC compliant Omni...which never did cover as well as Deltron.
You say other shops in your area are having the same concerns...are they using the same jobber? Are you mixing your colors or is the jobber mixing your colors for you? 8 to 10 coats, on a white, is just not acceptable or cost effective. I don't want to speak out of school here but I know of a local jobber that, in order to increase his gross profit was using more binder and even DBC 500 in the formula than the formula called for...if this is happening to you, (and I'm not saying it is) does your base coat after being flashed look silkier or even shinier than it used to...extra binder or DBC 500 will not effect the color but will give you a smoother looking pre cleared finish.
The more I think about it, the more I feel that something is amiss...even Omni, the toners where the same, they changed the binder and the reducer to meet VOC legislation. All paint companies have low hiders but 8 to 10 coats...Do you know these other shops well enough to have them mix a 1/2 pint of the same formula for you and see if there is a difference in coverage? That would be one way of checking up on your jobber...I'm not trying to point fingers, just discussing possibilities.
Are the reducer's the same as in the past? The regular DT line?
I've been a rep for PPG, Dupont and ICI (Nexa) and for a rep to say that the poor coverage is because of lowering VOC's...I would ask the rep what the manufacturer is doing to lower VOC's...if the reducer's are the same DT line and your using 2 to 3 times as much reduced paint...how is that lowering VOC's? If I was your the rep in your area I would mix a small amount and give it to you to try to see if there is a difference. Don't give up on this one...is there another PPG jobber in your area? If not, what about Dupont or RM?
Please keep me informed...I'm very interested and still have relationships within the three organizations...well 2 organizations since PPG bought out Nexa.