We learnt that having a read of the installation manual can be very helpful pre-purchase. In 2011 we bought a Miele cooktop that only had a statement "unsuitable for flush mounting in quartz bench tops" in that document, a document not generally available to the consumer. It was packaged in the box and normally opened after delivery.
No mention on the Miele web site, not in their catalogue and sales literature, and not in the salesperson's nor his manager's knowledge base. After all, who would want to put a gas cooktop flush in a quartz bench top?
One would have thought Miele would have been apologetic and eager to make amends, but the reverse was the case and they had the audacity to initially demand a restocking fee! . It worked out satisfactorily after we threatened to lodge a formal complaint.
Since then we have learned many built-in appliances have sometimes obscure and unexpected installation requirements from the screw down position to venting area, venting sizes, shapes, and locations, beyond what is in the glossy.