If you're comparing a DONE3 with a STAR fare, they're not comparable. One is segment based, the other is mileage based. Granted they may work the same for the trip you have in mind, but they're different animals. OW has Global Explorer fares that are mileage based, and if you're comfortable with that limitation, you should check them. I don't use them myself, but I think they're cheaper than the xONEx fares for the lower-mileage tiers.