What you are seeing from internal is actual amount of data being sent to splunk for the Series willie before it is compressed and reduced.
When you do the eventcount, that pulls the information for the indexed data on disk. So you can see that you sent ~33mb of data. Then the eventcount for the data is ~5mg. So this shows the compression that has been done on the index also. This is strictly event data, and doesnt include metadata or tsidx for the index though.