OK, so I finished a brewing new batch of Golden Strong (essentially the Zymurgy Nov/Dec 2009 p16 version) and I took an OG measurement of the wort in its undiluted state (straight off the boil and before top-off).
This was because I was mixing the top-off directly into the carboy and didn't want to reach into the final volume for a sample.
Anything wrong with this calculation? Wort vol = 3.2 gal, top-off = 2.3 gal, total vol =5.5. The gravity measurement of the concentrated wort was 1.12
((3.2 * 1.12)+(2.3*1))/5.5 = 1.0698 (call it 1.07 for calculated OG). The recipe as printed shows OG=1.08