Thank you for your question, Cag61! The shower flow rate indicated in the Technical Specifications refers to the shower head itself, which is currently rated at 2.0 GPM at 80 PSI (as of Oct 2018).
The valve itself will supply a flow rate. The shower port will have a maximum flow rate that is only slightly lower than the tub spout port.
Best regards, Jon
Date published: 2018-10-29