The BRS recipe is essentially RHF's recipe, but with a higher purity CaCl2 source. When I was dosing 2-part, I always used baked baking soda and BRS CaCl2. The calcium is probably dropping and your alk staying the same because you're precipitating out the calcium as calcium carbonate by overdosing on alk. Your alk level probably isn't dropping because you are adding enough to compensate for the precipitation.
In your situation, I would dose ~50-60 ppm CaCl2 in 2 25-30 ppm doses over the next day or two, and cut my alk dosage in half so that I'm dosing the same amount of calcium and alkalinity (or not dose at all if your tank isn't consuming much and you aren't in danger of an alkalinity crash). I'd take a reading before I adjusted my dosing, and then I'd then test at the same time the next day to get an idea of my consumption, using alk as my guide because it's changes much faster than calcium. Adjusting the dosing in a balanced fashion every time.
I'd then continue to test and adjust my dosing accordingly until my level stayed constant. At some point you might see a slight unbalanced consumption, but that will manifest slowly, over days-weeks.
