Hi Dave_C,
Thanks for the update and the additional information.
A 1/4" impression isn’t significant so you were probably experiencing some uneven initial softening with the mattress breaking in in combination with the effects of a mattress that wasn’t a suitable design for you in terms of PPP.
Whoever designed the chart you posted doesn’t know a great deal about mattresses or mattress design :). The types of “generic” comparisons they are making are more misleading than helpful.
While there are always some percentage of people who will do best on any specific mattress … you can see my general thoughts about airbeds here.
If you do decide to go in airbed direction … I certainly wouldn’t be looking at Select Comfort when there are other airbed options that use better designs and materials that for most people would be much better “value” (you can see a list of many airbed manufacturers in post #3 here).
Phoenix