Forums Scripts & Popups $send Displaying speed in KB/sec

Im using the $send to tell me the speed that a file was sent but the ones u both recomend me arent very accurate.. while in the status window and in the DCC SEND window I see the same speed is not the same I get from the script; its actually very different
I was also trying this $round($calc($send(1).cps / 1024),3) KB/sec but its not accurate either

Any Ideas ?....
Thank You !!