We went to the store where we purchased our current mattress and box springs 10 years ago (A California King mattress has two box springs). The salesman called for us to have a new inspection and told us to keep something heavy on the mattress to see if it will flatten enough for them to call it defective. Our mattress sinks 1 3/8". For them to say it is a manufacturing defect it has to be 1 1/2" .Is this crazy or a good idea? I'm not sure this will work, but will give it a try. They are not coming out for a few weeks. Would this really make any difference?

He also told us that since our boxsprings are like new if we got a new mattress from the same maker it would not affect the warranty on the new mattress. Is this correct? I'm more concerned about this than if they will call the mattress defective. I don't want to buy a new mattress made by the same company and have problems only to be told that we should have replaced the box springs when we bought the new mattress.