Can I reference models with masks in variant ModelReference?

Can a variant ModelReference be used with Models that define masks in R2017b? I have tried this for a pair of models with identical Parameter and mask sets and found no joy. The simulation appears to simply to ignore the model argument values specified for the variants in the Block Parameters Dialog and simply use those via the mask for the currently selected variant.

Worse, switching variant via Variant Manager etc resets the Parameter settings to the mask Defaults.