Originally Posted by xliioper

Since you are searching on roundtrip basis, the choice of return date can have big impact in the total roundtrip "From" prices listed above. Since you posted above, they opened 'L' bucket inventory on 6/23 outbound flights above leading to somewhat lower fares (L is one fare class lower than K fares).

BE/C+ fares use main cabin coach fare basis codes and "mirror" the Main Cabin fare filings. However, BE fares only go so far up the fare hierarchy before DL stops offering them (while C+ fare filings mirror main cabin fares all the way up to Y fares). On this route, the BE fares filings only go as high as T class and you will only see BE fares available for purchase when there is inventory in T, X, or V coach classes (even when there is inventory open in the BE 'E' booking class).