Say one SED.1 has a model attached to it, and SED.2 doesn't. Calculate fluxes under the fitted model for SED.1, where "Integrate Model" is checked "(YES)".
Switch to SED.2, which has no model. "Integrate Model" is still checked "(YES)". Then add a passband. An error with no message pops up to the user, and no calculation is done.
Say one SED.1 has a model attached to it, and SED.2 doesn't. Calculate fluxes under the fitted model for SED.1, where "Integrate Model" is checked "(YES)".
Switch to SED.2, which has no model. "Integrate Model" is still checked "(YES)". Then add a passband. An error with no message pops up to the user, and no calculation is done.