This has turned into quite a lengthy discussion ... there has been frequent mention of abandoning a multi-tower DA-N in favor of the non-D low power the FCC permits a station to keep after dark. I looked at the current facilities of a number of AM stations I had been familiar with in prior decades ... all known to have been fulltime with 2, 3, or 4 towers, and with anywhere from 500 to 5,000 watts night.
Here is at least a partial listing of stations that have gotten rid of the extra towers (and possibly reduced the amount of land), the cost of painting, insuring, and lighting the structures, the engineering expense, and the higher electric bill ... and apparently settled for the low power status...
WDAK 540 Columbus (went from 500 w DA-N to 38 w nonD)
WRCG 1420 Columbus (now 79 watts non-D, used to be 5 kw 3 towers?)
1460 Phenix City (now 140 watts non-D, used to have 3 towers I think)
950 Montgomery (was 4 towers 1 kw DA-N, now non-D with 45 watts)
970 Troy (now 45 watts, used to be DA-N with 500?)
920 Andalusia (was 3 tower DA-N, went to lower power non-D nite, then shut down?)
1320 Dothan (was 1 kw DA-N, now 92 watts non-D).
1170 won't do much with 7 watts night, but I wouldn't want the expense of keeping that DA-2 going. There are probably other stations in the area that have done the same thing as those I listed. (Now that 3 stations in the Columbus-Phenix market have downgraded, the Class IV station there on 1340 [1 kw non-D fulltime] looks pretty good by comparison.)