The big problem with d&d, is not necessarily the coverage, although that has to be good to support the weight of a
tile. The big problem is bed thickness, if you are bedding over the adhesives limits (5/6mm for most bagged adhesives of most manufacturers), you run the risk of excessive shrinkage and tiles debonding. I've seen it for myself today. 800x800 tiles d&ded. If the customer hadn't been on the ball, and notice the tiles coming loose, then one of them could have well fallen off the wall with the slam of a door.
Just because someone says they been d&d fixing in prestigious establishments, doesn't make them right.
Adhesive technical departments also get called out to such places, to resolve
tile failures.