This is excellent, thanks for sharing!

They've mandated its demolition but have allowed me to build an even larger addition (500 sq ft).The city is requesting building plans for this new addition.

Even google doesn’t have a street view of the house, so I need to be conservative here.Do I have any leverage in this situation?

This depends on the lender and what is charged in the orig fee.

Otherwise a simple $50 late fee penalty in the lease should cure you of this issue @Phil Shelton

Is this true?

I've actually been digging into this a ton recently. 

HH properties (and often HH clients) are high resource utilization accounts for a PMC, so many PMCs won't take them on, or will only take them on with the understanding that the property will be converted to a single-lease property (we do still use this approach.) 

Does anyone have a spreadsheet formula for this?

This is made possible by them setting up a Tenants In Common (TIC) structure.Has anyone done this before?