it just states that this particular dataset was 'applied in the determination'
I wish you well if you ever try to present that sort of nonsense to a judicial enquiry.
The specific FM will be the compilation of all of the negotiations, mitigations, and determinations for compliance of that specific variant
Indeed ... and the resulting document then constitutes the minimum Standards for the operation of that aircraft. Are you really suggesting that it is acceptable to plan and conduct operations in a manner unconservative with respect to the Approved Flight Manual ?
I take it that you have no legal competence ?