Corridor Point Control - Vertical Elevation and Grade

Having some issues trying to use a specific form of point control. Specifically the Mode - Vertical, Control Type - Elevation and Grade.

I am attempting to set the inslope to be variable using the point control. I would like the horizontal width of the inslope to be variable, the slope to be constant, but target a specific elevation. 

The point control seems to work in the corridor as far as the constant slope (1:3) and the horizontal distance being variable. But my issue is that it does not seem to target my specific elevation of (905.00)

Currently in the area of my point control the pond bottom (specific elevation) varies throughout. it seems as though it is just following a vertical difference with the profile? I can adjust the elevation in point control and watch the inslope shorten or extend depending on whether I go up or down. But still the elevations are not the same throughout the area.