Here's an update. I am now seeig a gradual increase in pH over several days. My Chlorine demand is much higher now that we're swimming alot and the weather has been very warm and sunny. I'd say my pool now more closely resembles the SWC model you're familiar with.

Typically I'll wait for it to creep up to 7.6, then I have to dose with a full gallon of Muriatic acid to get back to 7.2. After that I've been good to go for 1-2 weeks.