The Hercules is a very different beast to the ATR within ACL. The main issue is that because the main role is to be available on a 24/7 short-notice readiness the crews are all UK based and required to live close to the aircraft's UK base.
With a small number of crews, a rigid roster like that on the ATR does not work and days out from home vary greatly from month to month depending on what work the aeroplane is doing.