OK, if I understand it, your CC was 12.5 and now it's 7.5, that good progress. You need to keep it at the shock levels until the CC drops to 0.0-0.5ppm, the water is clear and you loose less than 1 FC overnight. This is called the OCLT in the PoolSchool. You need to pass the OCLT test before ending your shock process. The good news... once you get past this shock, you may not need to shock again, assuming you test your pool each day and stay current with your BB&B.
Adding more CL every hour is a great way to resolve this faster, based on the results of the FC/CC testing (each hour)
The 7.5 CC indicates the chlorine is still actively consuming algae and other organics. Are you sure the CC in your last posting was not your FC reading? The FC is the Free Chlorine available to clean pool, the CC are the Combined Chloramines and these need to resolved before ending a shock. TC is Total Chlorine and is FC+CC. This is what the OTO (yellow cap drops in the color block tester) tests for but most OTO tests top out at 5 TC.
I see someone's comment, if you used 10% or 12.5% chlorine, you can adjust for that in the PoolCalculator... and your FC/TC numbers would be higher than you expected.