I am trying this conceptually - Zorro 2.5.3

Optimize for negative range with min=-135 and max=-45
so that would look like this if allowed:
var LowerThreshold = optimize(-90,-135,-45,9);

But that throws a compile error and the manual says:
For optimizing negative parameter ranges, subtract an offset or add a minus sign to the optimize call.

So I tried this with a minus sign to the optimize call and it compiles but the value set is still positive (is this the right syntax as described from the manual?):
var LowerThreshold = -optimize(90,45,135,9);

The .par file shows positive for parameter 4 in this example = 90.4 and not -90.4 as expected (Is this possibly a bug?)
USD/JPY 13.13 34.1 98.7 90.4 18.00=> 2.504

I don't know how to "subtract an offset" as the manual says - can somebody help me understand that please?

I tried some things but always get positive parameter value.

Thanks!