I haven't seen the packaging myself, but based on what you're saying it sounds like they are just stating that the Bonus Features are in 1080p as well.  Sometimes the Bonus Features on HD releases are Featurettes and stuff that are in Standard def 480p.  So it's like a marketing thing that when they have Bonus matierals in HD they like point that out.

I believe the 2.29:1 is the aspect ratio of the feature although I don't recall ever seeing a 2.29:1 before...Bonus material, as stated, would be in the native 16:9 aspect ratio format, 1080p high def. Both are 1080p but I think they are distinguishing the aspect ratio there. I haven't seen the package either but that's my best guess on that one.

Well that appears to be the distinction they are making...Don't you just love all these numbers?