Output of submodel as input for migration

Hello there Forum members. This is my first time using the Forum as I've only been using Simile for the past 2 months. However, I've come across a problem that I'm hopeful more experienced users can help me with.

I'm trying to use the output of an adoption submodel as the input for a migration population element. Basically, the adoption submodel calculates the proportion of available land that will be dedicated to a given crop species. I then calculate the incremental change in this proportion using the delay function and feed it into the migration symbol. However, I've found that this method simply does not work, at least as I currently have it set up. When I run the model no new plots are adopted. I realize this method seems somewhat roundabout, as I calculate the proportion using a differential equation and then pull the increment out of that, but being a submodel it allows me to substitute in different adoption models as well as, and more importantly, use a separate time step for the adoption function.

I've found that I can work around the above difficulty by simply creating the adoption function within the migration element. While this correctly shows the adoption of the crop on new plots, I would really like the additional functionality provided when adoption is it's own submodel.

Is it possible to accomplish what I want using Simile, and if not why? I will gladly send both versions of the model if that would help. I've been looking over this for the past few days and for the life of me cannot figure out what needs to be done. Any help or advice would be appreciated.