Remember this little known secret called "real throughput" as opposed to the "nominal throughput" posted by the scoundrel ISPs.
When I used Dial Up the difference averaged 50%, and the first week of DSL was 80% (YES, an abominable 80%), although after tweaking TCP-IP improved by 450%, ball park figure.
Also P2P programs are just lousy at averaging anything dynamic, the worst being AG when calculating remaining time to completion.
The best route is using one of the many NET monitors out there, or using a Sci calculator and feeding it the function, the timing of a download and the unit used.
The results will NEVER match.
