Kharon - ASA has a "robust fatigue management system"
, but there are only 3 rules that are inviolate when it comes to overtime. 10 hour maximum shift, minimum 8 hours off between shifts and maximum 10 shifts without a day off (day off being 30 hours including midnight to midnight). Everything else is about mitigating fatigue risks, rather than avoiding it. We actually have some shifts where the official advice is to "nap on breaks", and probably like any fatigue management system, there is no such thing as too tired to work.
I think ASA management realised their mistake a few years ago, even if they never admitted it. The college has been recruiting and training people as fast as it can for some time, it's just not fast enough.
PS Scarily enough, the 10/8/10 rules are part of ATC employment conditions, not fatigue management, and so are up for grabs in the CA negotiations.