1970 Duster project in Sweden

Well, my spot repairs of rust turned out to be a big project that eats up a lot of time. It takes me ages because I have little experience. But I have patience so it's all good. Im getting close to do paint and have been at a shop to have them mix and match the old paint. I'm not sure that we will be able to get a closer match. This is two coats of top coat and 2 passes of clear. I painted a hard line on purpose so I could take pictures of it in daylight to bring to the shop for reference. The shop tells me it's impossible to match my sun faded paint. What say you?

Since I dont fully understand the world of paint and color I was under the Illusion that It would not be too hard to match it. The old paint looks lighter and more yellow to me, probably because it's sun faded. What I cant wrap my head around is, why is it so hard to make the new paint lighter and more yellow? Anyway, If it is impossible then I will do the best I can to work with this one. I'm gonna need to practise blending a lot. I was looking for information on that on this very forum. Do you guys have any links that I could read up on before I begin?

View attachment 1715003000
See the Gunman,out of Australia...(You tube,he is a interesting dude....)