I think the analogy Glojo is trying to draw is actually between scheduling sorties to be on task for CAS (ie as per the ATO) or holding them on a deck alert (with a similar response time).
This is not so much a question of response time, but efficiency and depends to a degree on whether those cabs on ATO CAS tasks are fragged for alternate targets as they approach Charlie time if no CAS requirement arises on the sortie, or whether they take their munitions home. If there are enough worthwhile targets for the for the former, then fair enough. If not, then a deck alert CAS task on the ATO might be a more efficient way of doing things, rather than keeping a two or four ship airborne from GdC, however long their time on task with AAR.
Nothing like Herrick as we "don't have" UK TIC, or JTAC on the end of the radio, so I assume the sorties being flown are more like BAI, rather than CAS.
In any case, as far as UK is concerned at the minute it's irrelevant until 2020 or so.