The only downside for me (besides debt service) is the opportunity cost of not having the money actively invested. 

During that deferment period, you should contact your loan servicer for the application to see which income-driven payment plans are available.

I have a 401k, Roth, and TSP from military service.

But don't you think that servicers still use this when you contact them to remove mortgage insurance? 

The purchaser takes the property charged with the primary liability for the payment of the prior mortgage and must therefore service the prior liens to prevent loss of the property by foreclosure of the prior liens.”https://www.jimersoncobb.com/blog/2012/08/special-considerations-for-bringing-a-foreclosure-action-by-a-junior-lienholder/

@Dina Harleth I am going to assume that your PM is also a licensed Realtor and is using the California Association of Realtors standard contract, if this is the case they will almost certainly not be willing to change it partially because it is against the California Association of Realtors terms of service and could also affect the contract as a whole. 

It's kind of like a mechanic...sure, lots of other places can change your oil but if one gets done quickly, provides good service, and doesn't overcharge you, then stick with them. 

Your debt service is almost close to the rent you are getting.

I have survived a long time in public service by always making the other guy look like the unreasonable ****.

All four duplexes are under one LLC and a single commercial loan is servicing the portfolio.