Now you've got me thinking! I've had to go out and check around. There's only the 'high bed' side where the cover provides deep cover (well, 4"). The other three sides only have a couple of inches of cover which are quickly used up with items stored under the cover (even the awning, if you're not careful.) It's enough, just, but certainly not excessive. One of the differences from the older covers is that the bungees for our cover are attached to a 2" pvc strip, welded onto the main body of the cover, a few inches above the edge. It does mean that the run of the bungees seem to hold the edge down better and prevents wind getting underneath. It's a pity that the cover wasn't produced with the depth that you are now benefitting from but with the bungee strip set at the same height, thus giving plenty of overlap but no problems with bungee tensioning. I wonder if it could be extended easily?
Also, having looked and tapped the panels, fitting another row of buttons could prove to be a problem as there seems to be a lack of secure anchoring places for them.
All this thinking has made my 'ead 'urt. I'd better stop and go and rest it