Is it possible that the ratios got mixed up a bit?
Before the patch you needed 800 Standard Panels to get the biggest one, outputting 48 MW. Now you need for a extra Large Solar Farm (100 for a Small Solar Farm, 2 for a medium Solar Farm [200], 2 for a Large Solar Fam [400] and 4 [!] for a extra Large Solar Farm =) 1.600 Standard Panels.
Or am i tripping?