SEA is currently

BA049 744 op Mon, Tue, Wed, Fri, Sat, 777 Thu, Sun.
BA53 Mon, Thu, Sat B777.

The summer is allegedly:

BA49 744 op Mon Tue Fri, 777 op Wed Thu Sat Sun
BA53 744 op Wed Sun 777 op Mon Tue Thur Sat. Only somedays the BA 53 leaves before the 49.

Confused...