http://www.reddit.com/r/HoloLens/comments/2tiun8/psa_field_of_view_of_hololens/
A lot of places were putting out pump pieces because thats what the MS fake-o-vision of course instigated (and it IS impressive tech aside from the unreality theyre trying to push so, preview hype was understandable), but digging you found the reality of the sort of sized rectangle viewing window you'd be getting. iPad at arms length was the middle ground of peoples comparisons.
Almost all of those claim a bigger FoV than what people have been talking about with the current version. We've known the FoV didn't take up your entire view.
A 15" laptop from 1 foot away is bigger than currently where people were claiming a sheet of paper at arms length. Even an iPad and half arms length is much bigger. In the latest article from Gizmodo is claims the current FoV is like holding your phone 1 foot from your face.
That's a big difference.
The Eurogamer quote from that link said "HoloLens' image doesn't occupy my entire field of view, but it takes up the lion's share of it with my peripheral vision grounding me to reality."
In ArsTechnica Peter wrote:
"And it's not just me; I talked to other journalists who'd been at the January preview, and they had the same experience. The January prototypes didn't fill your entire field of view.
The edges of the "screen" were visible. But they weren't this tight. I could look around a bit and still see the holograms. This time around, I couldn't."
So clearly there was a difference in those units.
EDIT: Just saw your edit - 30 x 18 to 40 x 22 is a 62% increase.