A new Ad Group - no change

Creating a new adgroup didn't seem to help. Keywords that had a Min Bid of .15 yesterday, and a good CTR for the day, are today Min Bid .20.

For example.. these 2 keywords were .15 Min Bid yesterday.
Yesterday's stats are:
One kw had 71 clicks of 1326 impressions.
CTR = 5.35% Ave CPC= .15 Current Bid was .16 QS was and still is "OK"

Another kw had 3 clicks of 41 impressions.
CTR = 7.31% Ave CPC = .15 Current Bid was .16 QS was and still is "OK"



Now how do keywords that performed so well (assuming 5+ % CTR is good) get bumped to a Min Bid of .20 for today. Again, neigher the Ad text nor the website changed last night. A kw that had CTR of 6.45% is still ranked as Great w/ Min Bid .05. Hopefully that will last at least a few days.