One of the issues with wider flat panels vs. the traditional high output fixed source is that wider panels will make some plants farther from certain LEDs. Not so bad if you have all 450 and 660 LEDs but if you start sprinkling in a few far reds in the panel, some buds won't see the light.

Unless you just went with many more bulbs or the sprinkled LEDs were simply higher output to reach better / broader.