From my experience that glide ratio may be a little optimistic since the engine is running and probably putting out some thrust. When you shut down the engine and stop the prop it may not be as good. I did an engine and prop stopped on my 12 at best glide speed of 60 knots and got 10.3:1, less than the generally recognized ratio of 13:1. The 12 wing airfoil should be more efficient in glide than the 7.
Since I just finished a 7A I am interested in any real numbers. Reviews of others POH charts shows glide ranges of about 1 nm per 1000' for a ratio of 6.4-7.2:1 depending upon the prop position.
Scott- 2019 dues paid
New RV-7A N579RV, 24 hours still in phase I
Built RV-12, 328 hours-sold, purchased RV-12 sold, Built RV-9A, 536 hours-sold, Not completed RV-7 sold, Built Kitfox sold