Functions inside Formulas error

Hello, maybe someone knows how to express functions like r_ticks(back_price, 1) inside Formulas. For example: IF(lay_amount>50, r_ticks(back_price, 1), back_price). In this case MF doesn't initialize r_ticks(back_price,1). So, in Log I get: IF(40>50, r_ticks(back_price, 1), 4.50)

Hi
Do you have a constant or user variable with "back_price" in its name - that would mess up parsing the formula.