Medium MF and BRRRR (Calculator) Questions

[Nik Moushon]

I'm relatively new here to BP so still trying to understand how everything works. I'm having trouble understanding how exactly the BRRRR calculator works in regards to MF. After putting in the purchase price and other info can the first "Purchase Loan Details" section be a traditional commercial loan to work out as a BRRRR or does it need to be a cash/hard money to work out right? Then the "Refinance Loan Details" section is just the adjusted new loan with the appreciated value so you can pay back investors. Not sure what I'm doing wrong here but I know I'm doing something wrong, because every time I fill it all out it comes up in some extreme negative cash flow number. So extreme that I know its wrong not just a bad deal since I filled it out with the traditional rental calculator and cash flows.

So there are really two questions here:

1) Does BRRRR work with medium to large MF? If so can you point me to some reading material on this? I know I'm not as read up on BRRRR as more traditional ways of doing deals.

2) Am pretty sure I'm using the BRRRR Calculator wrong can you help me out?

Thanks in advance. 

PS: Mods if theres a better fit for this elsewhere feel free to move this thread. Still getting use to your forum layout too.