Yamaha DTXpress/DTXplorer/DTXtreme

I've had my dtxpress 2 for a couple of months now and have noticed 
that the pad on my kp65 has a small indent at the top of its impact 
point.  My question is, does this effect the triggers response to a 
noticable degree and what problems should I look for before deciding 
that I need to replace the entire kp65 unit?  Thanks. 

Adam