I have always had a problem hitting off of hard, old mats. If a range does not repair or replace the hitting mats, they tend to turn into a something that resembles hitting off Hard Pan or like a Cart Path -- in my opinion.
You may not be getting the distance due to divots. The hitting mats tend to keep you clubface even with the ball. Now, at a Grass driving range, the clubface will take some of the grass, just like taking divots in the fairway while playing a round. This can, of course, decrease distance, if the clubface is not perfect with the ball. Hence, who's Clubface really is.......
Both Types of Hitting Surfaces can help your game. The Range Balls should go the same distance wherever, but I have heard that the "Floating Balls" that they use on Water Driving Ranges may not go as Far......