Heedm said; ~ I wouldn't say it proves I'm right, but it does support what I've said. It may be fluke that that one set of data worked out so closely.
It might be interesting to put the algorithms for calculation by gyroscopic precession and those for calculation by aerodynamics side by side. Then look at the sources of the data for each. This will show what inputs they have in common and what inputs are unique to each.
Another thought is to change the rotor's mass and see if it is possible to get the results from both methods to show a greater discrepancy.
Something for a very very rainy day.
Also, I just found a reference to gyroscopic precession in 'Helicopter Flight Dynamics: The Theory and Application of Flying Qualities and Simulation Modeling', 1999, by Gareth D. Padfield.
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It's appearing that there may not be a definitive answer.
Lu ~ Your use of gyroscopic precession may well be totally acceptable.