I use PrintBite surface on my PowerSpec 3D Pro (Flashforge Creator clone). When I print a model using Hatchbox PLA filament, I set the heatbed temperature to 60 degrees C and the extrusion temperature to 190 degrees C. The cooling fan is on 100%. The bottom of the model is "fatter" than the rest of the model and the corners are lifted. How can I fix the problem?