My assumption is that if I were to serialize the purchase event in the DTM User Interface with %orderID% would not result in s.purchaseID receiving the same value. Is that correct? I know someone out there has done this before, it's just a matter of implementing the proper process.
Your understanding is absolutely correct. If you use Data Element to serialize the purchase event, it won't update the purchaseID variable. Also, there is no field to populate the s.purchaseID in DTM tools/rules.
Hence, to set s.purchaseID you would have to rely on script statement as mentioned below:
s.purchaseID = _satellite.getVar("orderID")
You would need to have this statement under "Custom Page Code" of Adobe Analytics section in the rule preferable in the one which populates the purchase event.
Much appreciated. Meanwhile, it would be extremely helpful if this information were provided in the Help documentation for DTM implementation. I spent quite a while looking to make sure I wasn't missing anything before posting to the forum.