Jim,
that's a very small buy-rate for a whole lot of work both at the show and in post-processing. That was my issue with Agility events when I was shooting them -- I love doing it but the income stream just didn't add up to the time investment for me. At Conformation shows, I sell at the 80-90% level so I can pretty much predict my income from the number of separate win setups I get. Agility is all performance-based and if you get it, great. But if you don't, oh well!
I envy people like David who are not only good at it but are good at making it pay off from a marketing perspective. It's very hard work and prying money out of the hands of Performance Dog People is the hardest thing I've ever tried to do

. Good luck.
Jim