The NMBS (Belgian railways) keeps track of the delays each vehicle has. They use it to produce annual reports on the preciseness of their service. The aim is to keep delays to a minimum. However, I was told that, as long as the announced delay does not equal or exceed 10 minutes, they delay is dropped from the statistics.
I’ve been commuting between Ghent and Ostend for the past ten years, and it is quite rare that they use delays that are not a multiple of five minutes. So, perhaps this was a neat way to improve, shall we say, the annual report 
