is the yellowing in the lower fan leaves on your RO plants possibly a N deficiency? if the RO soil isnt quite as loaded with nutrients like FFOF is, then using the same nutrients in feeding both soils isnt really a good test. if the plants in RO are deficient, that would explain the slowed growth and bud production. it looks like there are more tops developed for the RO plants, so if more nutrients were added is it possible that soil would actually outperform FFOF?
edit: after looking at the pictures again, the red dwarf in RO is definitely potassium deficient along with the probably nitrogen deficiency
edit: after looking at the pictures again, the red dwarf in RO is definitely potassium deficient along with the probably nitrogen deficiency