+15pips is not a valid for "double" type variable (constant or whatever) at all. "double" variables - the values can be ONLY numeric values with floating point, such as 1.2345 or 2882.38387.
The value can be something like 0.0015 and then in "Adjust" you can put +ConstantName
The problem is that 0.0015 is a fixed number. Someone would recommend to write +toPips(ConstantName) and it will work, but this function is a custom function made by me, and at some point I may decide to change it or remove it