I agree. Long way to go. Starting to flush at just over 5 weeks is way too early. That plant looks very healthy, other than the nute deficiencies. I suspect it should go close to 10 weeks.
I stopped flushing years ago. I tried 2 plants side by side. Flushed only one and couldn't tell the difference other than the unflushed one yielded better.
I think you should reintroduce nutes slowly. Half strength first time, then full the second. I doubt the damaged leaves will recover much though. Stop feeding the tenth week if it makes you feel better.
Last point, if you're basing the flush or harvest time on the breeders catalog, DONT. They LIE! I think over time you'll find most strains need 9-10 weeks.
Again, that plant looks/looked great before you started to starve it. I might have to order some of those beans.
Fred