Should I REFINANCE a construction loan to a permanent loan OR convert to a permanent loan?

It seems that interest rates are much lower for refinancing existing loans, as opposed to new loans. I have a construction loan which doesn’t expire for a few months, would it be better to refinance the construction loan to a permanent mortgage or do a construction to permanent conversion loan? Which will get me a lower interest rate?

How fast should I refinance my car loan?

Car loan is 17000 dollars apr is 17 %.
Dealer told me that i can refinance in 4-6 months, but i think he lied to me. Bank told me that i can refinance only once.
So 4 months passed.
SHould i try to refinance it or wait at least 12 months???
Thank you.