0.7% out at 10volts is hardly the end of the world!
Neither is 1.1% at 20volts.
After all,the thing was on eBay,not brand new,so I assume it was cheap.
The easy answer is,just use your Fluke to set the voltages when they are critical.
There are a lot of other more important specs for power supplies than the readings on the front panel meters.
Have you checked for long term drift in settings,hum level,short term stability,etc?
By the way,I notice you changed the figures in your later posting--which is right?