@7e00ff73 >I guess one reason to charge only for upload is so that tier1s don't charge twice for the same packet.
Yes, even the greediest Tier1's are okay if their buddies or they got paid for the upload and are so "generous" to not double charge.

>I should just ask someone who works at an ISP around where I live.
Yes, you'll recieve interesting info as to how Tier3 ISPs operate around where you live and how the available Tier2's operate.