Thanks for the update, and I hope Mark's book is helpful.D)
I have been focusing on my fundamentals a lot (got Mark Wilson's book and have rededicated myself to a better stroke.)
Also, I've been working on progressive drills -- not unlike your drills, but just more general. For example: cue ball and object ball are one diamond apart, pocket the ball in a corner and follow one diamond, two diamonds, three, etc.
I've also been practicing my break. I've been trying to take some power off to improve accuracy and control... I've had some success but not enough to make me happy.
So I've been practicing a lot, just haven't done the BU drills in a while.
Please consider doing the exams and posting scores again. I look forward to seeing how much better you and others can do after dedicated practice.
Catch you later,