What am I missing with this FHA cash out refinance?

[Sam G.]

I've gotten great advice here from both experienced and newbie investors so I'm once again turning to my favorite forum for advice.

Currently house hacking and one year later I am ready to pull out some cash for my next deal. Lender said I can pull out $20k at 3.875%. I have to keep it as an FHA because my DTI so the pesky PMI stays. Overall the property cash flows about $500 but I recently got the taxes appealed so it will cash flow another $150. If I cash out, I lose that newly "earned" $150 so basically everything will stay the same.

I don't know if I should be looking at in terms of whether I should pull out the $20k. I know over time it will end up costing me more with interest but since it's being paid off by the tenants, does it matter? 

Anything I should ask my lender or numbers to run before I pull the trigger that I may be missing? 

I plan to buy my second house hack in about 1.5-2 years with that money and keep some for any repairs. Is it smart to hold on to cash that's pulled out for future use since you pay interest from day one?