Beags,
Thank you for the info.
Airbus will never see it a flight safety critical as the FMS looks after the tanker not the MPS. Airbus does not provide the flight safety case for the receiver. If the MPS algorithm is corrupted in any way then the resulting AP would be incorrect and may cause the receiver to fly to an AP and then divert without enough fuel, hence the flight safety issue. Any system below DAL C cannot be used to satisfy that requirement, certainly for the RAF, and so it would be interesting should we ever want the A310 to trail our aircraft using their MPS, one for the DH chain to consider maybe.
Whilst you could argue the DAL case against the cheap Casio calculators used by the crew, at least 3 are being used and cross checked for errors which therefore satisfies the safety case. As I am sure you know, the AARWIN plan is checked pre flight by the receivers to confirm that it is correct, admittedly a late notice change is harder to confirm as they do not carry their normal computerised planning aid, however, all endeavours are made to cross check the plan by another means and not just rely on the single source when outside of the stat met.
Like I have said above, I am sure your system is very good, however, it would not meet the flight safety demands of the RAF and so we could not just bin the A330 version and buy yours.