If you create a FuncList.dat entry and the generated C code is still generating the subVI call instead of the C function call, verify you restarted LabVIEW to reload FuncList.dat. After you restart LabVIEW, verify the subVI name in FuncList.dat.
If you receive compile errors when you build an embedded VI into an embedded application, verify the format of the C function call and the order of the parameters in FuncList.dat.
If you receive compile errors in LVFuncsUsed.h, verify that the third line is a valid C identifier.