You seem to be confusing bits with bytes in some of your posts. The highest speed you will ever see is 2.5 MegaBytes per second. Getting 2 MegaBytes per second would be acceptable on the 20mbps plan (80%)
What do you get at »speedtest.shaw.ca
? Make sure to test a few times a day at different times.
Are you connected directly to the modem? Are you using wirelesss or wired? Which modem do you have?
It looks like Nelson hasn't been upgraded at all yet as the fastest speed Shaw offers is 25mbps.
I am on BB100 and I can hit 72mbps on some YouTube videos. On a 20mbps line you will have some delay depending on what you are watching.
I wouldn't count on that NetIndex number being all that accurate overall.