My mooney is in the shop for an annual currently. The mechanic has identified several ICAs, instructions for continuing airworthiness, that apply for the Avionics installed--GTN 750 and GTX 330. He has stated that these have to be checked during the annual and he cannot sign off on the plane being airworthy without having his avionics shop confirm these. This isn't something I've heard of before, declaring a plane not airworthy due to avionics issues like this.. Is this accurate?