Although already answered the question, here's how licensing works with vCenter Server managing the licenses.
You will add the license keys you have to vCenter Server, which allows you to license each connected host by assigning the required number of CPU licenses to it. When you assign the 78 CPU license key to a host with e.g. 4 CPUs, vCenter marks 4 licenses as used, but allows you to assign the remaining 74 licenses to other hosts (from the same key) until all 78 licenses are in use.
You can assign any license key to a host, which has at least the number of licenses required for the host. This means that you cannot assign 2 license keys with 1 CPU license each to a host with 2 CPUs. In this case, you had to combine the two licenses to a single 2 CPU license key.
André