Mortgage Points Question

[Ana Marie B.]

Hi BP Fam!  Have a question for anyone savvy with financing or have experience with mortgage discount points.  So my husband and I have decided to upgrade to a larger primary home by purchasing a new construction single family house, while adding our current primary home as another rental. The issue is that the new build won't be completed until May 31st, with an extension clause in our contract for a possible additional 45 days (so on or about July 15th).  

We're concerned about the recent news of rising interest rates.  We're considering:

- 90 day interest rate lock, which would take us to June 20th or 

- purchasing 1-2 mortgage points at closing

The loan amount is $1,240,000.  So each mortgage point would cost us roughly $12,400.  Our question is, when is it "worth it" to purchase points?  What are the pros and cons given this current market.  Thanks in advance all!