After reviewing the Levitus et al 2008 papers abstract, (as I do not have access to the paper it's self), I assumed that the data you were referring to was based on some earlier data sets which seemed to demonstrate a ever increasing distributed localized temperature swing, when subsequent data, as indicated in the Levitus et al 2008 suggests a systemic imbalance of oceanic heat content increase in the range of a 0.31 Deg. (realclimate.org)
I just feel uneasy about accrediting a recent enhanced oceanic heat content to a purely physical process. (realclimate.org)
This study showed that the predictability of La Niña duration is controlled by the magnitude of initial oceanic heat content anomalies driven by the preceding El Nino. (usclivar.org)