Thinking of switching from HiLo to a level 2 count (probably hiopt2 or zen) but when I ran sims on CVCX, it appears that Zen Complete (full indexes) is consistently outperformed by hilo (full indexes). Any ideas for why this is happening?

6D 75% pen, h17 LS DAS RSA
1-6 spread

Is it worth switching to HiOpt2 with ASC considering the additional difficulty and learning curve especially since the BE is comparable with the much simpler HiLo?
If so, what accuracy would I likely have to get my deck estimation to?