please read my post here in my review thread:
I am curious if I am alone in this issue I am having with the control of the 99S? It's seems like it's either "feast or famine" for me with this stick and I don't know if it's me or the stringbed? I haven't had any of the string breakage issues some are having and I am not sure if this problem is due to the full poly job losing tension after a few hours or not? Maybe I should measure the tension with my iphone app and see how much it dropped since I got it 1 week ago?