There is no conflict between FDM and clearances deviation. If you deviate you file a report of the why and when, this is it ! If your Sops states 160 kt in approach, on my opinion they are too restrictive and innapropriate; SOPs are a framework to achieve goals, embedding techniques in sops just bring deviations in.
As a crew we are paid to make decisions, SOp's should cover 90% of our flights, the other 10% are specific airspace/airport/ whatever. And we file reports. Sops do not apply at Cat B/C airport as such, since there is specific configuration.
FDM is there to analyze tendencies, drifts, on crew performance or behaviour. It is very difficult for an operator to have in the same time the reactivity to correct innapropriate behaviour in a constructive manner and to have enough oversight to understand the in and outs of an event.
The systems are embedded, it is tedious work to make it happen in an open environment, it is difficult to trust the system at the beginning ( I was very skeptical at first); but it is like CRM, it does work...