You are still not getting it. Let's say there is a reduction in force that effects only NHCEs but isn't large enough to be a partial termination. Then you make actives 100% vested. There is a facts and circumstances part to the nondiscrimination rules that you need to be concerned about. This can look like you vested after removing a large number of NHCEs from employment and then targeted a group that includes the HCEs to become 100% vested.
It strikes me as a rare set of facts but My 2 Cents raises a valid issue. If nothing else the optics could raise more questions then it is worth.