Hey barnabythebear!!
Your render JUMPED from quality!!!!
Use your Dropoff now:
1) Enable Show Dropoff check box in the left collum of Area Light UI
2) If you are using 100% of Ref, Play with a smaller number, like 50%
3) You can balance Intensity value on general tab, using a smaller value and increasing the Over Intensity value on Dropoff tab which means, you make the light closer to windows more intense and let the corners darker.
You are mastering Photons barnabythebear!!!
Then, the second trick will be balance Photons Emissions, Area Light Rays Counts and GI Primary ray Count to have a high quality and a faster render.
Thanksss
Tom