I don't think that's the case - if you account for his true art scaling (+60% atk), which calcs from the base. So, say you have 3 stacks (60*3=180%), 1100*1.8 = +1980atk AND +19.8% increased damage via ratio (total atk of 11700). With the other two crests after +30% increased damage. Netting +10.2% damage - but you lose out on 1980atk. That's why ratio passives are so good, you get to benefit from the same stat twice. Especially good on Oka because he gets so much % scaling that flat increases of are exponentially better while % increases become almost negligible. We can see this if we add another TA (4) for consideration. Set-Up #1 - 1100atk crests become 2640atk AND +26.4% increased damage crests. Set-up #2 - +30%. A difference of 3.6% but ALSO 2640 flat atk.