We are observing that "delta per speed" is not working for items that "really" have the values close to the maximum of 64 bit unsigned integer.

• unsigned decimal with value stored as delta per second *
  

• unsigned decimal with value stored as is , referred to as PLAIN *
  

Result:

I have highlighted only those network interfaces which returns 64 bit counters.

As we can see, we get "no data" for the items where we have 64 bit unsigned value close to maximum of 64 bit integer.

This is causing issue while calculating some specific percentages for network interfaces involving these items.