I just reread your post -- I guess the hood picture was prior to your respray 13 years ago! I would never have single stage paint mixed with two stage -- on the same car. This must have been the problem with the match -- normally they have to blend the new paint to the other panels and then clear coat them - this way you can not tell -- never should you just paint one panel -- I see this on cars and I just can not believe it!
nothing wrong with single stage - most of the MB solid colors were single stage many years after they went to two stage on the others.
The single stage german paint - sikens etc is very good -- I used a single stage met years ago on a total respray that was great