I have a column called LOB. If the lob is “xyz” then the month of renewal is “6” months in the future. If the LOB is any other than “xyz” then the month of renewal is 12 onths into the future of the {effective date}.
This should work for your use case depending on what type of column the LOB column is. There are other ways to do this using formulas if your LOB column is a text/number column for example.