SmartBrowsing won't work with anything that is bandwidth intensive. It works with basic web pages and email and such, but not with pages that have streaming ads that pop up or anything like that. When the system detects sustained high bandwidth, it will disable the SmartBrowsing.
I can also vouch for the compression capabilities of the service. I've downloaded many things that should have used a lot more data than it actually did. With that said, I'm sure there are types of data that the service can't compress.
If during the homeschooling there are videos that need to be watched or streaming that needs to be done, it would be best to reduce the definition of it if you can. Streaming in HD uses around 3GB or so per hour, while SD uses around 700MB or so per hour and LD about 300MB or so per hour.
Did you provide the sales agent an email address when ordering your service? An order confirmation and welcome email would have arrived to you shortly after, explaining the allowance grace period for new users.