Effect preset duplicates effect rather than applying parameters to already existing effect

I'm having an issue with some effects presets I made. 

I have a simple set of presets that allow me to go into a custom side by side look for a graphic I use. Preset 1 slides a clip to the left and crops it using a custom keyframe "easing" curve (and is set to anchor to the in-point). Preset 2 is the same curve but it puts the clip back to where it started. Both presets involve motion keyframes (specifically the position property) and a crop effect with keyframes (and is set to position to the out-point).

The issue I have is when I drop both presets on the same clip, it creates 2 crop effects and they get in each other's way. What I want to happen is for Preset 2 to add it's crop keyframes to the crop effect that already exists on the clip. The motion parameter already does this.

Currently, I have to set both presets to anchor to the in-point and apply a cut on the clip before I drop the preset on. This works, but I want to have both presets applied to the same clip rather than 2 clips. This way it can be easy to keep track of which cuts are for transitions vs just edits. Am I missing something in my process or am I stuck with things how I currently have them configured?

The image I uploaded shows how the crop effect is duplicated and the motion effect isn't. I want the crop effect to work like the motion effect is working