Iron Harbor is the only mortgage company with the Optimal RateTM  analysis report

Once you lock your loan with Iron Harbor, we will prepare our proprietary Optimal RateTM analysis report. 

This is a tool to help select a rate.  It takes the lender origination cost or credit from the quote/lock (the yellow highlighted row) and treats that as either a cost or credit in Month 0.  Then it  shows a running  subtotal of the upfront lender origination cost or credit plus the cumulative interest paid, plus mortgage insurance (if applicable) for each rate.

In the initial years (for instance in year 0) the highest rate is typically the lowest cost because you will not have been in the loan long enough for the interest savings at the lower rates to make up for their higher upfront cost.  Over time though, the lower rates will catch up.  The question is how much time? 

The Optimal RateTM analysis report answers that question. You can go through it row by row to see which rate produces the lowest overall cost based on how long the loan is out.