Download speed limiting causes High CPU usage

As the title says, applying any download limit causes around 30% increase in CPU usage on my machine. That’s more than 1 core on my 4-core i5 7600k.

Refer to this URL for an example because i can’t give links imgur(.)com/a/gDzpUhY

Not bad, considering games will use all of your CPU at 100% if it can. But this is just a launcher. Not even that, “Blizzard Update Agent” is the updater for games installed on your device.

Yes, I’m aware that its not just simply downloading, it’s also decompressing and installing, similar to Steam downloads. But why the sudden increase in usage? 30 times more compared to without a limit?

Is it taking advantage of the limit in network usage to start decompressing the files? That would be smart, and I’m hoping thats what it is. But I’ve already seen one customer support grunt disregard this as normal behavior and, out of their hands (in the category of Desktop App Tech Support):

us(.)forums.blizzard(.)com/en/blizzard/t/%F0%9F%90%9E-battlenet-download-throttling-still-has-a-bug/3145/2

So, what now?