vSphere Data Protection VDPA license for kit, must license 6 CPU or the actual no. of CPU in the cluster

Licensing expert, I need your advise.

I understand if I have 3 hosts 2 CPU each in an Essentials Plus Kit or VSOM AK, then I mus license 6 CPU, not partially.

But if I just have 2 hosts 2 CPU each in the kit cluster, do I buy 4 CPU VDPA or 6 CPU?

Thanks!