I spoke with Colin Veitch about this yesterday. The pricing policies will be in a state of some fluctuation over the next short while, while they "play" with the pricing to try and gauge their response.
The plan is to charge $10 in the Tex Mex for a time on some ships. If the reaction is negative it'll disappear.
The spin (if you are a cynic and want to judge it that way?) is to see optimum use of all restaurants onboard, and lower the chance of line ups at any.
They'll judge success by that criteria...and pricing will reflect what works best to achieve that goal.