2.2.1.2 At units where workload for any part of the day is judged to be low and the activity is spasmodic rather than continuous, periods of operational duty, at these times, may be extended to a maximum of four hours, provided that the following break is taken pro-rata (e.g. 45 minutes after 3 hours or 60 minutes after 4 hours). (see Note below)
Much of the activity in Ireland outside of Dublin Terminal Area and Shannon Highlevel with the Atlantic Rush focused on the Irish Landfall points would come under that heading.
There have been various occasions on which closures would have taken place but for the presence of multi-rated staff. It's a good thing for management that they never got too far with their plans to split the roster and de-rate staff.
The whole idea of multi ratings - something that is a requirement to be employed at most other providers is to enable a more efficient staffing level.
In terms of de-rating, are you talking about a similar situation as the Manchester situation where controllers did aerodrome and area disciplines before management split the two despite being co-located. Despite being started in the Early 90's it was "in preparation" for a move to a then unknown location for the ACC. Some would say that it was to prevent ACC controllers having the ability to try and swing a stay put in Manch by virtue of their aerodrome qualifications. Moralle is similar on both sides of the Sea it seems!
Regards,
DFC