To understand why fretted instruments don't play in tune you might want to read THIS article. It isn't long.
Yes, we can send a man to the moon, but we can't as yet defy the laws of physics, which is what you'd need to do to make a stringed fretted instrument play perfectly in tune all over the neck. If you think your instrument does play perfectly in tune, you need to read the article!
The best we can do is achieve perfect equal temperament, and that requires a compensated nut as well as a compensated saddle. Both of which can be done. And perfect strings. Which don't exist. Mandolins are high tension little beasts so the errors are not as bad as they are on guitars. So a compensated saddle is all you really need to get "close enough for jazz" as they say.
In the end, no matter how much you spend, or who makes it, all you can do is get close to equal temperament, then live with the compromise and get on with the music.
As has probably been mentioned (I've not read the whole thread) off the shelf mandolin bridges tend to be over compensated. You can always get your local luthier to make one closer to how it should be.
Nigel
http://www.nkforsterguitars.com/
Bookmarks