Using a 16A energy monitor in a 10A socket
When electrical appliances talk about Amperes it usually means 


how much max POWER it can OUTPUT
or 
how much max POWER it can MEASURE


In your case, the spec actually means not to exceed the 16A limit.

So if you are monitoring a 10A socket that is well under the spec. So you will be fine.

As long as you do not exceed the 16A monitoring device limit you will be OK.

Usually in home applications.. you will(should) never actually have anything even close to that 16A limit. Power leads are typically marked 16A maximum to conform to electrical and home safety standards.



16A X 220Volt = 3500Watts

You will only see devices use more than that in Industrial situations and usually run of multiple phase supplies and massive core cables.