Saying this will "definitely" result in better UZR numbers for Markakis and Jones is overstating things a little. Maybe it will, maybe it wont. Either way, it's certainly an interesting angle because, you're right, their numbers were always worse at home.
What I don't understand is why Buck and the front office would care about improving their UZR in rhe first place. It's just a measurement. Improving it doesn't improve their actual production (compared to the opposition). If their numbers are worse than their actual production, wouldn't it be best to take advantage of the information asymmetry and keep it to yourself? Unless you're trying to trade players, and want their league wide value to go up, it's beneficial to keep what you know to yourself by allowing the rest of he league (and the players' agents) to continue to rely on the flawed numbers.