I recently (December 11) upgraded my 14-day ultimate park hopper ticket to an AP. I got a Gold AP since I am a DVC member. I was shocked that they only charged me 68$ to upgrade the ticket. The ticket was originally 299 GBP (I purchased just the ticket since we were there for 11 days and I am a DVC member, so I only needed the ticket). The Gold AP DVC price is 584 $ (including tax). I have no idea, what exchange rate they used to determine the 68$, but I did not complain. The current exchange rate on December 11 would have meant that the 299 GBP would have been 368 $, so the upgrade would have been over 200$. I cannot even find a recent exchange rate that gives me 516 $ for 299 GBP. Of course with the 2017 tickets the upgrade price could be different.
For whatever reason, the AP also came out as valid from December 11 on (intead of from December 3 which was the first day I used the 14 day ticket).
All in all, I was totally excited about the great deal I got. Because of the current promotion I even got an AP that is valid for 13 months and I was able to get the discounts on merchandise and food.
Of course once you are looking at package deals, those might be better than the AP. And a Platinum AP is also less of a deal than the Gold AP that Florida residents and DVC member can get. So, it might be less of an advantage for you. Just wanted to report my experience because I was thrilled by how well it worked out.