It is possible, but unlikely.
It is possible you have a high volume node, or they were doing some work in your area.
I am very fortunate that there are only 4 people on my node

so traffic is always low and my speed is always fast.
Do you have a static IP? if so That can sometime create a restriction, due to the route your data needs to take.
If you have a dynamic IP, he may have just issued a new one(if he asked you to reboot, than he definatly did), which on occation instantly increase your speed, due to the route your data takes. If you are in a highly populated area there may be many nodes accesible to you, some will definatly be faster than others, simply due to the number of users on each.
You can test this out if you have a dynamic IP, aquire a new IP and tast the speed of it, then try another and so on, once you have found one that is faster, set it as your static IP. Sometimes the cable company wont like it much, but they hardly ever check to find out.
EDIT: You can try different ways to optomize your system to take full advantage of your conection. There are hundreds of sites about this, here is one I have used and had good results
http://www.speedguide.net/downloads.php 