FWIW...the navy reg sparked my interest, so I decided to do a sanity-check of my AF reg today (AFI 11-202 v3), and it clearly says you do not need to call and close out a flightplan if you land at a towered field.

"3.1.5. Closing the Flight Plan. If operating in the NAS on an IFR flight plan into an airport with a functioning control tower, the flight plan is automatically closed upon landing."

I'll admit to my guilt....old habits die hard!