Be careful of playing the numbers game like you are, an increase of 60% for the Tundra, would only be a 10-15% sales difference in the F-150 sales. The F-150 still sells 3-4 times the same amount trucks that Tundra does in a month, and Ford didn't meet the incentives on the hood of the other full-size truck manufactures out there last month either.
Unit sales can't be correctly judged till the old Taurus sales are finally out of the system, which should be by December of this year and Ford has stated many times over that they want to keep a 13% market share (which has kept), since thats their baseline to be profitable after the restructuring and will grow it once its done restructuring...