Evidently not, since there are many AMs with night power so low that the coverage is literally four or five miles.
Yes it is.. 250 is the minimum day and not for new licenses.. what you see is stations who have been around before that rule was enacted and are former daytimers given night power or those who downgraded. You can be a Class C/B/A well above 250 and downgrade.. you cant build new under 250