It's a cost of doing business.

my goal is to keep it as simple and low cost as possible.   

There is a significant upfront cost associated with this but I have calculated it will average 2.2 years per building to save the cost I’m currently paying for oil.

If your operating costs are below the market, your NOI will likely be matched closer to the appraisal's market rents.

That gives me additional income and offsets the risk of loss if I have a longer vacancy once they leave. 25% sounds like a lot, but consider what it will cost them to find another rental in the next 30 days that will allow a three-month lease, plus the cost of moving, setting up utilities, etc.There's nothing wrong with trying to help out a good tenant, but don't hurt yourself in the process.

so, just something for you to think about - that a 3 or 5 or 7 year hold period probably won't get you enough appreciation to offset transaction costs. 

There are closing cost so either you will need to pay all those or have some downpayment to cover them otherwise the seller is paying to offload it. 

 $150/month is nothing… and given your closing costs of say $16,000 if you sell, it would take 8+ years to recover that $16,000 at $150 per month.  

A lender may want all properties insured by the same company with the same renewal date, so you may need to adjust things and see your agent before applying for a blanket mortgage simply to know what the costs will be. 

I am in Florida as well up in Pinellas by the Gulf Beaches and know that Miami is costly!