I have a Vapor V2 87 flex. I've had it for a while but have not used it very much. I tried an X60 87 flex and it feels like its stiffer. Shouldn't the flex feel the same since they are both rated at 87? Is it possible that the V2 has softened with use? I get a nice kick off the V2 but the X60 feels like it take more effort to flex. Thanks.