Any paint store worth 2 cents can supply the same color in the better quality paints. I used Deltron on my charger 22 years ago and it still looks awesome. The cheaper lines are for collision shops that are trying to maximize their profit margin due to being controlled by the insurance companies.
After getting SEVERELY BURNED by a paint counterman's advice years ago, I then chose to go to the local paint rep for whatever brand you choose, I tell him what I am doing, and ask their advice. They normally recommend their more expensive line as I want it to last. if one doubts what they say, check the MFR's compatibility information and you will typically find that the cheaper base coats are not compatible with the more expensive topcoats, Regardless what the 15$ and hour counter man recommends. Contact the local rep, ask his opinion, get his advice, and follow it to the letter, from the bare steel, primers, sealers etc. Unless of course your just Flipping the car to maximize your profit.

BTDT