I think anybody mentioned that he did that before - go search. I would think it wont help since in my book the A4 is not too far away from a A5, but it cured the boominess in a my neck DiMarzio PAF.
I run now a JB with a A8 in my maple/alder strat. Great combo far better than the standard but it has not the beef of my Custom 8. The Annihilater (Wicked Lester called it so) rules by far.