Let me say right off the block that I have no experience with this test, so I'm just thinking out loud here: $5 a test sounds good, and that you can run it yourself sounds great, too. Having to run the test 5 consecutive days if you miss that 1-22 day window (which is based on experience with cows) suddenly ups the cost to $25/test (unless the negative appears before day 5, but still)...not good. Then in my experience heat cycles of goats vary tremendously between breeds and somewhat between goats. That puts the question out there if that timing of running the test on day 21 after AI/breeeding is actually correct for YOUR doe.
Hmmm, I think I'm going to let someone else try this one!