Unanswered 3D Printer Code: Marlin Babystepping Axis Issue

Hello all, novice here, I'd appreciate your help in resolving an issue.

I've set up Marlin Babystepping for my 3d printer and have hooked up a dedicated lcd to it. Currently, when I start the print and move the dial, the extruder only steps up (not down), and only does so when the printer is printing in the negative y direction.

I have played around with making the multiplicator a negative value, but it didn't seem to help. Regardless of whether I turn the dial left or right (i.e. positive or negative), it makes no difference. The extruder only steps up (i.e. moves in +z). Never down (i.e. -z, which is what I primarily want it to do). And, like I said before, it only does this when the printer is moving in the -y direction. +y, +x, and -x do not register/process any input from the dial.

I'm using a modified version of Marlin_RAMPS-Epcos_i38 with Arduino 1.6.7.

Any help will be greatly appreciated. Thank you!