I don't think you can't get deltaware Cultured but the off-the-rack part of Type O System seems to indicate Augmentation's RAW considers it to only apply to non-Cultured, as Kiirnodel quoted. The idea there being that not only should it be Standard grade, it should also be off-the-rack Type O, which Cultured isn't.
Also, Type O System applying to just Basic bioware can still be worth it to a full-bioware character who's looking forward to Orthoskin, Muscle Toner, Muscle Augmentation, Bone Density Augmentation, Platelet Factories, Symbiotes and more enhancements. It costs a lot but really pays off in the end, saving you an easy million or more. So from a player perspective, I think it's definitely worth the BP in the end, assuming your character concept works with it. If the player is informed in advance it won't work on Cultured and still makes the call (such as my own character concept) it pays off quite nicely in the end. The money saved on all that Basic Bioware can rack up to more than Deltaware Synaptic Boosters Rating 3, still cutting your costs in half if you get those as well.