It is maybe that the insurance company are aware that the site is routinely checked every six months and tested every year, and as Dave alluded to are happy with a three year report.
But I would agree with you too, it would be a brave man/woman to recommend an EICR greater than the guidance , given the notes in the guidance, and the way litigation is now.
As long as you put your period of next inspection on the report, it is then up to the owner to follow that or ignore it.
We cannot police the owners . As long as we comply with the requirements of the statutory bodies in the notes, and the report is accurate , the rest is up to the owner/operator of the site.