auto channel distribution

[tschaps]

I just finished my deployment of 60 MSM430 and MSM466 AP with a MSM765zl controller team in a school. The 5 Ghz radios are set to Auto 20/40 width and auto channel, and an 8 hr interval, no channels excluded (I tried a time of day interval early in the morning, but this particular problem was worse). I can't believe what poor use this system makes of the available channels. In fact, a quarter of the radios have settled on channel 36, a further quarter on channel 44, and almost a quarter on channel 52. The distribution list is below (U.S. channels):

Ch    APs

36     15
40     0
44     15
48     0
52     11
56     0
60     5
64     0
100   8
104   0
108   5
112   0
116   0
132   0
136   0
140   0
149   1
153   0
157   0
161   0
165   0

I understand the system leaving the channel gaps to make room for the 40Mhz channels, and I plan to set this back to 20Mhz to see if that helps, but I would get a better range of channel use with less overlap if there were a setting "random" --

At one point, I had all three APs in a gym all choosing channel 60, even after multiple restarts. Everything is running 5.5.3.0-01-10326, if that matters.

I know there are some older posts lamenting poor channel choice, but is this seriously what others are experiencing? BTW, the 2.4 Ghz distribution seems OK. I have all but 1,6, & 11 excluded, and 21 APs are on ch. 1, 21 on ch. 6, and 18 on ch. 11. I have not sketched it out to see which ones are adjoining though.

Thanks for any insight on whether AP channel distribution is some rocket science I am missing, or if we might petition HP to just put a "random" option in the auto channel settings (I am serious).