I watch the download speed rise and fall like waves in a storm. At night, during low bandwidth usage I have achieve speeds as high as 3.23 M/sec but the watch them decline to 250 K/sec. and then climb back up. Over and over. During the day my best is around 1.67 M/sec with lows into the 65 K/sec. On top of this, why does a download need to slow down when approaching the end of the download? It's not like a multi-hundred ton train needing to decrease speed as it approaches the station.
Your download/upload speed depends on a lot of things. For example: