You can hold off on the 2nd shock for now -- keep testing 2x per day, but don't add any more chlorine so long as levels are above 10 ppm. BTW, your pH test may, or may not, be correct. High chlorine, in the absence of extremely high CYA, causes phenol red (the pH test indicator) to read 'high'. (Chem_Geek, do you know whether the effect is the same when CYA is this high?)

But, meanwhile we need to get a little better idea about your CYA levels.

Steal one of your wife's measuring cups and a clean container. Put one cup full of pool water in the container, and then add 3 cups full of tap water. Mix, and test. See what your CYA level is, and report that here.

Ben