Well fortunately were talking about Bendix mags andrew, the periods of maintenance which is set out in the MM, as highlighted in the SB, maintained under the CASA regs, enforced by and audited by their surveyors.
I find it it perplexing that people are using an example whereby an SB was missed, under which the airlines own SOM would have directed it to have been addressed either way, the result of which summoned an enforcement by CASA of said SB with threat of grounding, followed by the AD, for a defect that had the potential of a major disaster. If you want to give me an example whereby the SB shouldn't be observed this one is definitely not it.