How can I get a P3 to read flow sensors on level ports higher than port 2?

The only options in the flow sensor settings in PLC for "Flow sensor connected to port" is 1 or 2. I have 4 flow sensors connected to a PLM4Level interface card in the P3 itself, not an expansion box. The level sensor diagnostic shows ports 1 - 8, and the red light is blinking on the interface card (in slot 2, but I've also tried it in slot 1). Running firmware 5.16 beta and PLC 5.1.6.1, both of which I believe are the most up to date versions.