Multifamily Millionaire book capex and repair calculator question

[Annchen Knodt]

I just finished reading Part I of Brandon Turner's new Multifamily Millionaire book (great book!) and am wondering if anyone can answer a very small clarifying question that came up when I was checking out the calculator spreadsheets in the bonus content (i.e. the Multifamily Capital Expenditure Budget Algorithm and the Multifamily Repair Budget Algorithm).

The end result from the calculators is called the "Moving Baseline Number", which is a term I haven't heard before - can anyone provide any additional context on why it's called that?  It's pretty obvious that the number represents the monthly amount to budget for the respective capex / repairs, but I just like to generally make sure i'm getting lingo straight and not missing anything.  Thanks!