Am I too picky (Turn-key house wanted)?

I'm currently in the market for a turn key property--my first investment property (I'm 52 and have owned several personal residences). I've engaged with several TK providers in multiple markets.  I just can't seem to find a property that meets my numbers. I'm searching for a SFR in an A to B- neighborhood in the less than $150k price range. The numbers I'm looking for are ~10-12% CoCROI and ~$280+/month cashflow after all actual and estimated expenses/reserves. I'm plugging the numbers into the BP rental calculator using 7% for vacancy, 7% for maintenance, and 10% for PM. Is that too much to ask? I see a lot of properties that are being sold but none seem to meet these marks. Am I in the analysis-paralysis phase?? Do I need to lower my expectation (and be more realistic)?

Thanks in advance for your advice. 

Shawn