When you do a funding position in Mercury you will notice there can be a few different LMI premiums listed for each lender. This happens because there can be different premiums depending on the type of loan you are getting.
Each lender will have a note. It's important to check that the LMI calculator can be used for your scenario.
CBA premiums have a note next to them explaining that you must use the CBA LMI tool for self employed, refinance, cash-out, rental properties, or FHO
The reason for this is because some LMI Premium Calculations are dependent on the loan type, and some are just too complicated and varied to be represented in Mercury, so the lender calculators need to be made use of.