Ppg has a tight hold of their distribution. If you want to use another brand or two stage, you can save money. The dealer I went through is the only place to buy it in central Florida.
My tcs is painted with concept single stage, and after 5 years, it still looks perfect, which is why I paid the money.
Your choice, but for me, after a year of labor, it makes sense to use what you know.
Btw, I paid retail since I am not a pro with the pro discount.