Wow, interesting question. FWIW, I'd include it as compensation for 2013, use the 2013 deferral election, and ADP test it for 2013. (As an aside, many docs define the compensation for a plan year as W-2 for the determination year - the determination year being the plan year in the absence of any other election).
While I recognize the 415 issues that must be considered, I think the document language (if defined as above) provides sufficient justification not to re-do history going back possibly several years. It's also more "reasonable" as far as I'm concerned. The potential problems and expense involved in retesting, possibly failing, top heavy, HC determinations, etc - you name it, are so ridiculous that I'd absolutely avoid it if there's any reasonably justifiable alternative. In fact, even if the document language is silent, which seems unlikely to me, I think I'd still do it based on 2013.
That's my story and I'm sticking to it. Until I change my so-called mind...
P.S. - I sincerely hope I never have to deal with this in a real life situation!