mississippi fan,
What device are you performing the rescan on? Is it a TV, a tuner box, a DVR, etc?
Are there other TV's or devices in your house that you have connected to the antenna, in addition to the one you're having difficulty picking up WAPT 16 and WDBD 40?
I live near the Reservoir, 24-26 miles from the towers in South Jackson/Raymond. I just rescanned for channels on my 2009 32 in Sharp HDTV. All of the subchannels for 3, 12, 16, 29, 35 and 40 are being properly mapped in the channel list, so the PSIP channel information is correct at the station.
If you can pick up WMPN 29, you ought to be able to pick up 16 and 40. Fun fact, 3, 35 and 40 are all on the same physical tower with each transmit antenna at a different height on the tower.
Have you entered your street address into
Antenna Signal Prediction yet? This site can assess how well stations should come in at your location and accounts for changes in terrain between you and the towers. What colors does it show for each of the stations in question? Based on your information, it sounds like you're somewhere close to Brookhaven.
Without knowing more, I would guess that the tuning device you're using to pick up the stations is going bad, you have a glitch in the coax wiring or the antenna itself has a problem. Another thing to check is to make sure there is no other object made of metal any closer than six feet to the antenna (other than the mast or mounting bracket for the antenna of course). This can cause bad multipath interference.