I have seen related questions to this in posts that are 6 or 7 years old, but have not found a good answer. The DELV_NUM element is in the WSDL, but I believe it is marked as optional and mybe the reason suds ignores it. I did not make the WSDL file and cannot make changes to it. If I can modify the suds message to appear like the Soapui message, the response should work fine. I am limited to patching and modifying suds, as it is part of Inductive Automation's Ignition platform.
This is the message request sent from suds
This is the message request from Soapui using the same WSDL
I can share the WSDL if that would help. Thanks