This looks very much like an own development, I would certainly not take this to SAP.
SAP is consistent, if there is a table field identical to a field in the screen then the values are shown 1:1.
there might be more fields in a screen than in the table, those are then computed during runtime.
Your case looks like this "tracking number field" is only used as an output field for some other value.
A programmer should be able to determine at least the program name and then he can check
if there was a modification in your old system e.g. from SE38 via the program versions
or he uses this guide to find the potential exits or BAdIs