Lower your interest rate mortgage calls are very poorly targeted. The companies that do this get lists of people with mortgages, which is easy because mortgages need to be publicly recorded to be effective, and call all of those people without any attempt to narrow the field; or maybe they just call everyone they can. They usually call and offer "new lower rates" when the rates have gone down in the last few months, but they probably don't work very hard to estimate the original rate (it's not public record, but you could probably make a good guess based on the lender and the date it was recorded).

I had a mortgage originated in 2009, and then rate adjusted down several times to something in the 3.x range -- and would get calls and mailers promising "historically low" rates of 4.x; which I always found very amusing.