From one cow versus 100 cows trimmings, and a $1pound cheaper. 

This requires doing math, patience and a learning curve.

These are professionals with additional training and a stricter code of ethics.

Also, if a few hundred dollars in draw fees will make your deal go sideways, it may not be the best deal for you, especially as you are just getting started.I'm happy to share my experience as an investor and a mortgage broker.

Down payments on DSCR purchases can be as low as 15% right now, and as you noted, they don’t impact your DTI.

I have financed a number of STR properties and they will usually be appraised as a pure real estate as vacant value and a cash flow adjusted commercial value, sometime separated as going concern and real property.  

Still have a lot to learn and a lot to ask before I'll be ready to start though. 

A colleague of mine has bought two properties owner-occupied back to back in Arlington (with a 5% rate and a 7% rate) doing basement conversions and renting rooms, lowering his effective monthly payment on each property to sub 2K each time.

@Zach Howard there is no agreed upon Classification in the 1-4 unit market.We've done our best to logically create a system for our market, mostly based upon relative sale prices, but also using crime rates, rents, occupant income and a few other variables. 

An experienced agent will list your property with the language, "no showings until an accepted offer", to avoid violating your tenant's rights to the peaceful enjoyment of their home - possibly resulting in their lack of cooperations and a lawsuit against you.