FCC DTV vs analog coverage change maps

[Robert F. Sutherland]

Broadcast Engineering Magazine online 1-01-09 article 
refers to  Dec 23 FCC publishing of  Expected DTV coverage by market.

It predicts WBPX-TV Boston, to have a gain in coverage area 
(i.e. no viewer losing analog service and 1.1 million gaining digital
service)

  To view the maps visit: 
 http://www.fcc.gov/dtv/markets/ 
and   ("significant changes")
 http://www.fcc.gov/dtv/markets/report2.html 

Analysing the maps, I am surprized that the majority  
of stations are show to equal or somewhat increase coverage with DTV.
Moreover,  I keep noticing station cases where
DTV power is greatly reduced from analog power,  yet maintaining coverage
area!

  I assume the DTV contour actually represents 99%+  achieved digital lock.

  I wonder what standard the FCC used for  analog contour, possibly
something like 64dBu?
  Translated to viewability, does this level represent consumers only
willing
 to watch "perfect" analog signal, no snow, etc?  

  In all, please could B-R-I members (especially the more technically aware)
 comment on your analysis & perceived believability of these maps?

shaking my head in wonder.....

Bob Sutherland