this might work:
[LegacyColorValue = true];
input: FV(68.18), YM(c data1), INDU(c data2);
var: diff(0);
diff = ym - indu - fv;
if diff > 0 then begin
setplotcolor(1, darkgreen);
end;
if diff < 0 then begin
setplotcolor(1, darkred);
end;
setplotwidth(1,1);
if...