Temperature Regulation

Hey guys,
First time using a freezer and temp control unit to ferment.
This morning I realized that my carboys were reading higher than my target temp. Target temp was 68 degrees - using WhiteLabs yeasts - British Ale yeast and English Ale Yeast.
The carboys were reading 72 and 74 degrees, due to the activity of the yeast. I kicked the temperature control down to 65 degrees to compensate. Now, 16 hours later, the carboys are reading 64 and 66 degrees (off of my target).
Questions...
Knowing the actual temperatures (within the fermenting liquid) may be higher, should I make the adjustment back upwards.
Also, are there any negative outcomes to fermenting at a temp that is just a bit too low for the specified yeasts?
Thanks!

Usually, in the first few days of vigorous ferment, you'll have to set the temp 5-10 degrees cooler than your target due to the heat generated. You'll just have to then bring it back up to your target after that first ferment. You'll get a feel for it.