Modeling flow through a valve

Matlab 2019a with simscape

I'm trying to model flow through a valve. I have several manufacturer datasheets with valve properties, design operating conditions, and a Cv curve. In simulink/simscape, I model the valve as a "Variable Local Restriction (G)". With area as a function of Cv. I attach a "Controlled Reservoir (G)" upstream and downstream, to set the datasheet's operating pressures and temperature. The resulting Cv vs Flow does not match the datasheet, nor any of my companies other valve models. It is not off by a factor of discharge coefficient either.

I have also tried the "Ball Valve (G)" model, with no luck their either.

Has anyone else encountered this? Is there a better way to model a valve?