allocation of excess assets limted to 8% for non-actives

Code 4980 says that the excise tax on a reversion is limited to 20% if AT LEAST 20% of the surplus is allocated to plan participants. But it further indicates that not more 40% of the allocation can go to non-actives. And that even if more than 20% is allocated, only 40% of 20% - 8% - can go to non-actives. So for instance if 50% of the surplus is allocated to plan participants, 42% must go to actives and only 8% can go to non-actives.

Am I reading this correctly?