Hi jet7571,
While each person may have a different “personal value equation”, I normally suggest that a 20% difference between a local manufacturer and an online manufacturer in an otherwise apples to apples comparison would be roughly equivalent “value” because of the benefits of being able to deal locally and test a specific mattress in person but of course each person may be different in the number they use or which of the different options or features offered by each manufacturer is most important or “valuable” to them.
In most cases people will have determined their best configuration well before this time but either way (whether you are exchanging layers or just using or re-arranging the layers you have) you would be “using up” the time for a refund. I’m not clear on why one would affect the other when it’s just an additional option. A refund is normally the last option and used only when there is no configuration that will work and it would be rare for someone to have to use it, especially when they’ve actually had the chance to test a mattress in person and it’s only a matter of “fine tuning” th layering if necessary. It’s an option of last resort in other words that would be by far the least common scenario. It’s always a “hassle” to return a mattress though not so much because of the cost involved but because of the time involved in re-packing it and sending it back and then having to start all over again from scratch.
That would depend on the size and on the softness/firmness and on the type of latex (Dunlop is heavier than Talalay and firmer is heavier than softer) and on whether the layer was split or a whole layer. As an example if the latex was 5 lb/cu ft then a 3" queen size layer would be 8.33 cubic feet which times 5 would weigh about 42 lbs.
I personally can’t imagine the vast majority of people taking that long to decide whether their mattress could be configured the way they liked it (and especially with Habitat which doesn’t offer custom layering that can be re-arranged or exchanged anyway so your purchase choice would be the only option you had) but like anything else if someone believed this was important enough then they may be willing to pay the premium involved either in price or in the lack of layering options.
Phoenix