Mystified by name range adjustments

I have got the attached spread sheet from John Walkenbach’s book. I could not figure it out how he got "Number of Periods:" 240.00 automatically change.
I have looked at the range names. There is no dynamic range. All it shows on the range name is the “payment period” is in the range A9-A45. If I change the values in B4, all rows on the spread sheet are adjusted automatically. For e.g. at the moment the period number is 240. The rows go down from rows 10 to row 249, but If I change B4 to 24 periods, not the only the rows are adjusted on Payment period Column to rows 10 to row 33, but all other columns as well.
How is this possible, and where is I am missing? Please help