10Mbps versus 100Mbps Cable Modems

[fbsd2]

Am I missing some thing here? 
I though 10Mbps/100Mbps ends up controlling the 
max packet size traveling over the internet.
So if your using 10Mbps, you end up generating 10 separate 
packets versus 1 packet at 100Mbps to move the same amount of data.
This results in a network using 10Mbps to have more administrative 
overhead that a network using 100Mbps. This overhead on a heavily 
used network results in longer lag times in receiving replies.