How did Fury's punching power change so drastically?

I hadn't heard he intends on coming in heavier. I think that's a mistake. If true, I guess Deontay thinks he will benefit from the extra weight. Guy is so goofy maybe he doubled down when somebody told him the extra weight is no good?
The torn bicep thing was me being devils advocate. I personally don't put a lot of stock in injury claims unless they clearly happen during the bout. I've always thought these millionaire businessmen could find a doctor willing to fake a report. Make a small incision and stitch it up, claim they had shoulder surgery whatever.
I'm a fan of neither man, I'm a fan of boxing. I think Fury will win this time, don't really know how. I was rooting for Fury the first fight cuz he was the underdog in my mind. I'll be rooting for boxing saturday.