Here another Y-up fare from SEA on UA:

ITA routing:

From: sea:: sfo phx phl tpa
To: eyw:: tpa phl phx sfo

Class: Business class or higher

sample dates: Aug 18 - Aug 22

Fare price is USD 852 (=599 Euro) for 9,122 rt.-miles; this eaquals to 27,366 BMI-miles (*A-miles).

regards