Mode of Transport Preferences

I am getting confusing results while setting up Mode of Transport Preferences.

I have setup the preferences for Customers Only.  It means the following preferences will apply to all items.

ID        Customers                Mode of Transport         Sequence

1          1234                         AAA                              10

2          4567                         BBB                                20

Problem 1:  When I enter the order for Customer 1234, I get Mode of Transport "BBB" instead of "AAA" at line level.

Problem 2: When I enter the order for Customer 4567, I do not get any Mode of Transport at line level.  I should get Mode of Transport "BBB"

Please comment.