I would agree - I work for another DUB user, and our flight planning system fuels us for the full arc on the arrival. I have been in and out fairly regularly over the last few months and generally gone at least half way round the arc, with the odd bit of holding thrown in too.
Suggesting we fuel for only a part of it and use our contingency if need be is a bad, bad idea. Imagine we have burned our contingency avoiding CBs en route for example. I just can't see how level flight at 230kts round the arc is in any way more efficient than doing a CDA under vectors, even with frequent use of VS.