Bravo trip report, nwff!
You did everything right, from pre-ordering the Obento to keeping on Pacific time.
Sure, the Obento is mediorce at best by sea level standards, but at FL370 its about the best a health-conscious pax can do.
Agreed that Changi is a terrific place to turnaround in. Plenty to keep yourself occupied for 7 or so hours if you choose not to snooze at the transit hotel. I've not done the transit hotel shuffle myself, but wouldn't hesitate to try it the next time a good fare from PDX comes up.
I hope you do get a chance to spend a day or two in SIN. Not only is it a great bang for the mileage run buck, but it's just a great place to spend a couple of days. And I could wax rhapsodic about staying at the Conrad ...
I'm looking forward to my third excursion there in March,