What formula does WIC authorize?

Basically my son had a lactose sensitivity when he was born so doctor wrote a prescription to give to wic for Similac sensitive which worked great. Months later he was 5 months old and started getting constipated and very firm poops. I tried changing the formula to enfamil reguline as many people said it was good. I did this for a few days as an experiment. He was pooping normal again. Then i went back on similac sensitive, long behold more firm poops again that he could barely pass it so i know its the formula for sure. Now he just turned 6 months and wic been called me 3 weeks ago for a phone interview for his 3 month renewal they do here. So they've already prepared what they'll load into my wic card which im suppose to go in tomorrow to do but their closed right now so i can't call to find out if they'll change the formula since it hasnt been put into my wic card yet. And if they will cover enfamil reguline. My son has a checkup on the 6th and i can easily have the doctor write out the prescription then but im hoping wic works with enfamil. I know they've always worked with Similac. Anyone ever had to do this? I live in PA btw.