This does not directly apply to your question but it is related to using SIPs.
In some two story home designs you will find the designer has called for the 2nd level platform (floor joists, subflooring, etc) to sit on top of the 1st level panels. Then the 2nd level panels sit on the 2nd level sub-flooring.
Other times the the designer will have the 2nd level platform hang from the top of the 1st level panels. Then the 2nd level panels sit on top of the 1st level panels.
Obviously the 1st level panels in the second case are going to be taller then the first case by the thickness of the 2nd level platform.
Of course you may have panels that span both levels but that's another issue entirely.