I've had no problems transferring national accreditations obtained outside services to CFS, CFA, ForestrySA and MFS. I think they're all happy they don't have to pay for it
That is the general idea behind national accreditations - transfer without hassle. Sad to think I've just been lucky and there have been issues for others with this.
I think it will only get better. Even in as short a time frame as the past five years there is a much better framework behind training, better understanding of national accreditation within services, with transparency of competencies involved, which makes for consistency and acceptability across all organisations. People might complain about having to do training again for things they are already qualified for, but that's what recognition of prior learning is all about.
If a service wont accept an accreditation then they should get on board and suport the review or development of training packages rather than complaining about the inadequacies of ones that exist.