That sounds about right. Not just Audi. My previous Mercedes had the same issue. After a couple of services the dealers apparently considered one grommet was perfectly fine for the holding the engine cover in place. After buying new grommets, my solution was to put a smear of silicone grease in the holes of the grommets. This allowed the cover to be fitted and removed easily without pushing the grommets out of place. It still stayed in place with no problem.