spacing the IVIG out

Hello everyone, last time I saw my neuro, he said I was doing so well I could try going to IVIG every other month. At the moment, I am on 10 mg of prednisone and 75 mg of Imuran. I am also about 5 and a half weeks since my last IVIG treatment. I am feeling and have been feeling pretty good. My fingers still get a little tingly on and off and I have some leg cramps and can’t run that great (but I never could). My question is, should I, if I get closer to my 8 week scheduled IVIG, and still feel this good, should I ask to prolong it a little more or not? The cost of the IVIG is a big issue for me and if I don’t need it, I would like to not have to pay for it. I am just not sure how one goes about spacing their IVIG treatments out. As I’ve said in previous posts, I’m not sure if the IVIG has helped at all or if the steroids have done it all. Any thoughts?