Its hard to say how much degradation you get from inconsistent ferm temps but two things are empirically true. My split batch experiment showed me that even a 3F difference in temps had huge impact on top character. 66f was crisp and bright while 69F was muted. Most people that bring me beers to troubleshoot, Diacetyl, Acetaldehyde and other problems were also correlated with no temp control. When yeast makes its own heat you want to cool it. When the heat wanes, you want to keep it warm, or even warm it up to quickly process out the byproducts. It was also mentioned before, but post ferment oxidation will strip hop character very fast. Look into low or no O2 transfering.
I can't speculate why extract batches were different other than seasonal diffences.
I can't speculate why extract batches were different other than seasonal diffences.