It would make sense to me if someone was hugely over because of period 1 (i.e. year 1 - year 3) and then made massive strides in the right direction year 4.I cannot see why a second breach would lead to a suspended punishment. That makes less sense than a suspension for a first punishment
Even if they still failed the test for years 2-4, do they deserve a similar punishment if they've made a big improvement? I'd say definitely not.