At around 750 miles, mine just dropped to 90%. That works out to about 6400 miles to 15% life (assuming it is linear). I thought it would go 10k between changes based on my driving but I does not look like it based on the first data point.

Has anyone checked to see is if it is roughly linear?

 

if your drive pattern is the same, would expect it to be linear.... it does have adjustment for time too