Your monthly payment is now much cheaper at $.50 and you will put a renter in the house who is paying you $.80 - so you will make $.30 a month in cash flow, which your girlfriend will demand you spend on her.

So I just don't know if the market is demanding more.

Do I play hardball and risk losing the deal or just accept to buy at my original full price offer?

your credit, and history, experience plays in to the rates, then 3. does the property cover all expenses with profit. 

To @Gita_Faust 's comments maybe it's an import from your tenant software, trying to get it and QBO to play nice together.

My biggest issue of the way everybody talks about BRRRR being amazing is the cash flow is usually really low unless you refinance less than you're investment or have a ton of equity and amazing rent demand.

I know there is some demand in my area from people wanting to rent a similar space.I found one property I am considering buying.

To really maximize your STR profits, you need solid year-round demand.

If she's being difficult with me showing the unit now, then it's probably naive to expect she'll suddenly start playing ball after I change the keys.

This was a long term residential "slightly value add" play.