So, here's what a rep from an unnamed SEM agency said:
"Google defaults to the ad destination, even if there is a keyword destination. However, when we change the URL destination in the ad, it won't impact the QS."
I may have had a long day... but can someone chime in here? Not impact the QS and restart it?! Some of these KWs, URLs, etc. were gaining traction over years... Backup? Rebuttal?