It's quiet difficult to understand modelling from a textual description, attaching a screenshot of your model or an exported project would greatly simplify things. I suggest you attach either and I'll be happy to respond.
One thing that does sound wrong in your description, is the flow into <Value>. Chooser/Selection Field display the options received via the <Options> element, whereas the value selected by the user can be read from the <Value> element.
I also suggest you take a look @ http://www.tersus.com/#Id=315, which demonstrates functionality similar to what you seem to be trying to implement. Note that this is actually part of our step by step tutorial which you can follow from http://neweb.tersus.com/#Id=121.
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