FC7 Plum Crazy Purple paint question

I bought a gallon of FC7 recently using the paint code. I then tried to buy some in another paint line (2 in fact). The paint dealer spent a lot of time trying to match the first one and couldn't do it. There are so many variants it seems. Without a sample you are going to get what you get. I doubt the primer matters much but I didn't experiment. The paint I used covers very well. I believe some paint lines will tell you what color primer to use. I saw a chart somewhere...can't remember where. Gray was correct for purple.