Keep in mind @Mario Morales that they take premiums, invest them so there is a profit component on invested returns, and hence amplifies how far the $ can spread on payouts. less than stellar returns and expanding claims, yes, rising premiums is a certainty. 

To determine the best option, we should run the numbers for both scenarios and see which is more profitable.

Changing whole buildings over isn't always practical (or prudent) and we will be running buildings profitably with galvanized pipes in the walls for the rest of my career. 

They could provide the funds needed to complete the project in exchange for a share of the profits.

If you don't have a unit open to cycle each tenant through while you renovate them, you don't have an option because things will keep breaking when occupied and you will be getting less and less rent and no profit for years.

Profit margins are tight and every penny counts.

We have a handful of properties in TN and MS, mostly older homes and maintenance is starting to dig into our profits. 

I am concerned that he/she is either filing bogus small expenditures OR performing services himself/herself and making profit.

They tend to be more flexible than institutional lenders and may lend based on the equity in your property or its ARV, rather than focusing on your income or DTI.If you have any connections with investors or family/friends who are looking for safe investments, you might be able to pitch the project to them, offering them a higher interest rate than they would get in traditional investments.Advantages:More flexible terms.Negotiable interest rates and payback periods.Considerations:You’ll need to clearly outline the project’s profitability and how you will repay the loan, usually through a refinance or sale after rehab.

In the spirit of non profit you would be helping people collect this overage and NOT charging them.