Is this possible?  I want to do a design study where I have a downward force that is always half my upward force.  The idea would be to iterate through a range of upward forces, using an equation in the parameter dialogue to keep the relation between the two forces.  I've established Simulation Parameters for the Design Study called Upward Force and Downward Force and linked the values to forces in my original study.  In the References Item Selection Box of the Design Study Parameter dialogue, SW is calling my upward force Force-1@Study Name and my downward force Force-2@Study Name.  I've tried every variant of syntax I can imagine to establish Downward Force in an equation to be half of Upward Force and can't seem to get Simulation to accept it.  Any suggestions for what should be in the expression box (see attached)?

Thanks!