If the seller agrees to the terms, that's fine. But I do not think this should become the norm. Where a seller is responsible for not selling a cracked or broken bat (things a seller can readily observe), compression numbers are not readily available. AND, some bat testers are novices and will return invalid/inaccurate results. Maybe they test the wrong (or right) spot, giving a reading different than that confirmed by the seller prior to sale.
To me, this is a slippery slope, an easy out for someone with buyers remorse. "Failed compression, take it back."