Gordon,
Impossible to determine without knowing all your swing numbers. Best solution might be to just try adjusting the loft up and see what happens on the range. One thing to remember is that when adjusting your loft up you add some additional spin into the equation.

Simply increasing loft does not necessarily mean added distance...there are many factors that influence each persons optimum club setting and shaft choice. Others can comment on the technical factors. I play a 9.5 D3, have a steep angle of attack (-3.5 degrees) and as a result have too much spin on my ball. If I increase the loft on the driver my ball is much shorter. The best thing to do is go to a fitter and have him/her assess your swing and club and shaft choice.
Bob J