Battle.net is not recognizing a limited Bandwidth speed

When I set a limited speed to 256 KB/s

Unfortunately, it won’t recognizing a limited bandwidth speed.

Instead, it will go more than the maximum bandwidth speed (which is around 2 MB/s), like 2.50 MB/s or more, if it’s more than 2MB/s it will illegitimately cause internet major nasty lag.

Please Fix it.