just to be sure, which "5x5" are you refering to? alot of members here mean bill starr's intermediate or advanced program when they speak of 5x5. i'm not sure what you are doing but if memory serves me right you do your own 5x5 split.
anyway - if you read madcows site you'd know that you NEED to ramp weights every week and that given a caloric surplus in diet, you WILL grow. why complicate things?