Short answer, no. pH calculations are exponential. That means a reading of 5.0 is 10 times more acidic than a reading of 6.0. So a 4.0 reading would be 100 times more acidic than a reading of 6.0. When you look at it that way, it's easy to see that 1 ton doesn't necessarily raise it by even increments. I don't know how the recommendations are calculated so I can't give you an estimate. I can say with confidence that spreading 2 tons would not raise your pH above 7 if it currently reads 5.4. A $7-$10 soil test should give you an accurate recommendation.