Brian speaks the truth.
Metallic paints have tiny metal flakes in it, you knew that. Here is what happens. If you spray dry, the flakes tend to stay oriented they way they hit the panel. If on edge, that stay on edge. If the flakes hit the panel flat, they stay flat.
Flakes laying flat reflect more light, making the paint look lighter. Flakes on edge do not reflect as much light, and the paint looks darker.
If you spray wet, the flakes tends to settle to a flatter orientation. This is why if you do not spray metallic paints with exactly the same overlap on gun passes, you get "tiger stripes"
So, to match the paint on the car doing a spot repair, you have to match every condition you had when you sprayed the car the first time. Same temperature, same humidity, same paint application conditions, every thing exactly the same. If you are very experienced spraying variables are reduced. If you took extensive careful notes of how you sprayed the car, you might be able to reproduce the results.
So, if you really want to redo the paint and body work, you can. It is your car. But there is a very good possibility you will have to redo the rework a few times to get it right.
I suggest if you decide to redo the car, take very careful notes, and the results of the paint. If you do not like what you see, the notes will give you an idea of what not to do.