That's correct. I also use 256 kbps service. 27 KB/s is the maximum speed I get for downlds.

256 kbps = 256 kbps divided by 8 (8 bits = 1 Byte) = 32 KB/s minus overhead = 27 KB/s approx.

ie: overhead loss includes various factors such as how far away you are form the phone exchange, etc.

So kbps = kilobits per second & KB/s = kilobytes per second

Remember 8 bits = 1 byte