For this purpose, deductions are more or less calculated in the same manner as you would calculate ordinary deductions so long as they are associated with the passive activity for the tax year or carried forward from a prior tax year.
Couple that with processes that seek certainty at the expense of creativity and calculated risk taking and you have the perfect mix for incremental results or worse yet, market failure.
But there is a gotcha, namely once you have filed for a retirement benefit (regardless of whether you have suspended it) your spousal benefit will be calculated as the excess spousal benefit rather than the full spousal benefit.