STA question

[Gary's Ice Cream]

If a radio station is licensed for x,000 watts of power into a directional
array (different patterns day and night) do they need to get an STA (special
temporary authorization) to drop down to less than 1/5 power
omni-directional?   How long is an STA good for?   If they have been doing
it for well over a year without filing for an STA can there be serious
ramifications?