moonpie, sorry for the delayed response!
Really, I don't have much to add. I think you have already identified the value of the evaluation you already had (ID'd as intellectually advanced-->school responded with academic advancement), and the indicators that it is a likely low estimate of ability (inexperienced evaluator, inconsistently motivated/engaged examinee, divergent/unconventional response style). As you note, if your child is happy, growing, adequately challenged and developing holistically, then there is not necessarily a problem to be solved. I love that she pursues her passions at home, and clearly finds home and family to be a secure, safe place to be fully herself. For someone as internally motivated as she is, academic acceleration will have to be as joy-led as everything else she does so evidently is.
My thought would be simply to continue monitoring and listening to her as you have, taking seriously any changes that suggest that she is becoming distressed or feeling constrained...and give yourself permission to enjoy the journey. FWIW, despite being a professional evaluator, I have never had my children formally evaluated.
If additional testing does ever become relevant, do some research in your community first, to identify evaluators with experience and appreciation for intellectually gifted learners, and with any other exceptionalities that might be in play at that time.
