I'm going to try and get a copy of a book called Faster Isn't Smarter. It expands on the ideas discussed here:
http://www.mathsolutions.com/documents/9781935099031_message18.pdf
DD7 has a much lower PSI relative to her other scores. Next week her teacher will start giving them "Math Minutes." DD7 hated these when she had them in K and it was a relief when her 1st grade teacher didn't use them. I'm hoping DD7 won't have a setback in her attitude towards math because of these timed drills.