Sounds like you're on the right track. On my i1pro2, the readings are different between using a powered hub and going direct to the usb port on the laptop. The presumption is that the powered hub has the correct voltage and the laptop output ....well, you just don't know. lol
After using a powered hub to power the i1pro, then be sure that you've got your grayscale right. Then do gamma, then back to grayscale and confirm gamma. Then do color.
Which calibration software are you using?
Samsung 64F8500, Panasonic 65VT50, Oppo 95, Tivo Roamio for OTA, Dish VIP722, Marantz AV8801 preamp, Rotel Amps, Atlantic Tech 8200 speakers, Seaton Submersive HP, Calman 5, Chromapure, Accupel DVG-5000, VideoForge HDMI II, i1Display3pro, i1pro2, eecolor colorbox.