1 time financed mortgage insurance

[carrotsmakemefat]

I assumed the PMI we’d be paying on our home would drop once we hit 20%.
We are putting down 10% on our home.

Anyway, I found out today I am slated for a one time financed mortgage insurance versus the mortgage where PMI drops after 20%.

My lender is talking to me tomorrow about it. I’m just confused because I always thought PMI would drop, or you’d refinance to drop it.
I was hoping with the market increase that any appreciation would help me get to the 20% more quickly.

Has anyone done the one time financed mortgage insurance ?