Vertically uneven brake pad wear

[timothy]

Last weekend I drove a DE at Eagles Canyon Raceway and used a new set of Pagid Orange pads. They did a great job.

After the DE I found two of the front pads had vertically uneven wear: one with 9.2mm remaining on the top and 10.4mm remaining on the bottom; a second pad is 9.1mm top and 10.3mm bottom. Both of these have little bits broken away along the top (narrower) edge. I think the two uneven pads were on the inside but am not 100% for sure. Horizontally the wear is very even with left and right edge about the same.

The car is an 03 base model with 82k miles. Any ideas? Is this something I screwed up when changing the pads or simply a matter of age?

I figure the uneven pads need to be discarded after resolving the problem but with another DE in April I am tempted to use these again and fix the problem in May. I hate to throw away brake pad that still have 2/3 life remaining. These things ain't cheap.