Collection variables and formula fields...

Thank you for your help.

I am trying to use a collection variable to bring field values form one form to another - one them is a formula value. I have been able figure out the collection variable (I think) Some values (publication) will come over but not the formula value (insertion cost). Here is the script written:

PropPub1 = LUX_Enrollment [Street_Address == input.Prop1];
if (input.Prop1 == PropPub1.Street_Address)
{
    if (PropPub1.Pub1 == "")
    {
        PropPub1.Pub1 = input.PubNameLPC;
        PropPub1.Pub1Cost = input.Insertion_Cost;
    }
    else if (PropPub1.Pub2 == "")
    {
        PropPub1.Pub2Cost = input.Insertion_Cost;
        PropPub1.Pub2 = input.PubNameLPC;
    }
}

I really appreciate any guidance!