1stclassradio
Even if KXEN isn't goint to use the STA for 330 watts, it is still unclear to me whether they owned the property on which the towers are located or not. Thus, it also remains unclear whether or not the STA was an emergency of their own making or of someone else's making. I don't mean to imply anything sinister by that. It's just not clear (to me, at least) from the FCC filings whose property was sold that created the need for the STA. More power to them, figuratively at least, if they can manage to keep their 50KW/500w signal.
As far as 630 AM is concerned, it is my understanding that that frequency has been licensed for 5KW full-time in St. Louis since 1940. To my knowledge, it has never been licensed at any different power level since then and has never been a daytime station (at least on the current frequency). So, unless you are speaking of 690 AM, which, to my knowledge, is currently and has been since 1948, a 1 KW daytimer, it is not clear what the station is to which you refer.