3engnever, sorry, but my feedback is from all users...
The DAL 'C' required of the Voyager MPS is for reasons other than AAR planning / management, because it is used for other purposes for which legacy methods are used by A310 operators.
The requirement for the A310 MCS was that it would never be required to be a 'standalone flight safety critical item'..... Mission critical, perhaps - but flight safety critical, not required. In the highly unlikely event of it failing in flight (which could only be as the result of a 'double failure' of hardware, there being no single point failure risk), that wouldn't stop any AAR.
As for not requiring fully independent DAL certification, that was customer-driven to save time and money. In the same way that they didn't expect an electronic calculator to demonstrate a DAL....