It only appears to be low because they are reporting corrected alkalinity which is only the carbonate alkalinity. It's a disgrace that they still call this "Total" Alkalinity. CYA's contribution to alkalinity is real alkalinity.
The only reason to subtract it from total alkalinity is to use the resulting carbonate alkalinity to calculate the amount of carbonate in the water for saturation index calculation purposes. This should be fine internally by their software.
Calling this still "Total" Alkalinity is just a scare tactics to sell more overpriced baking soda to their customers. They are basically hooking customers into a subscription scheme. By reporting TA lower than it actually is, means that the pool is way overcarbonated, resulting in CO2 outgassing, driving pH up. This will be fought by adding acid, driving TA down again. Add baking soda and start again.
Great business model. For them, not the customer.