Silvers are not that bad of a problem, If you have taken your car to a bodyshop and are paying top money, you should expect an invisible repair, unless they have told you otherwise before carrying out the repair. But to get a good match on these light metallics you do need to have a large area sprayed.
A bad blend will show in the sun or under forecourt lights, petrol stations,
Is your mind playing tricks with you, are you seeing things because YOU know the where the repair was?
If a few other people can also see the blend then the bodyshop will have to redo the job!