I think the issue is simply "octaves UP" vs. "frequency ratio". To get the frequency ratio you add one to the middle column of numbers. I believe this is where the "minus one" comes from in the original equation.
This puts the original +7 semitones at 1.49 something, just about 3/2, remember our ancient tunings... then 12 + 7 comes out at almost 3.00, twice that... I've stopped worrying about it, although for some reason I dreamed about taking a history test that had no questions on it.
Thx again.
DL
Finding pitch shift coefficients
Moderator: frank