Rate Buy Downs

When I talk to borrowers about if it makes sense to buy down a rate or not I always frame it in the cash/cash flow world of cost vs savings & time to break even. I got to thinking that I am missing part of the equation which is how much interest they will save at the lower rate on the loan itself. I put together this spreadsheet to calculate savings depending on how long they are in the loan. I feel like it should be part of the conversation but don’t want to overwhelm people. Wondering who else brings this factor into their conversations.