Mr. RT. IF you are able to take a piece/sample to a good paint store they should be able to scan and match it exactly. Older paint may not be the same color/tone as the original. You can also buy flattening additives.
No, don't do that. "Light Straw Yellow"? Sounds so...country. Barn like. Go with "Candlewax". It's the same color. Just sounds better. Very elegant.
This is how my wife chooses paint colors. Two paint chips, exactly the same. One named "Elephant Dung" and the other "Grassy Fields". Shes going with "Grassy Fields" every time. Will actually hate the color "Elephant Dung".