But as yet not reported, you can use proxy servers if you want although I don't bother.
Proxy servers won't help. The ISP can see all your traffic because your gateway to the Internet is a machine that they operate -- or at least that their supplier operates. I think I feel an idea coming on... no, scratch that, it's bad.
I thought it was 1024 Mb in a TB?
TiB. The official SI multipliers are 10, 100, 1,000 etc. but geeks started to use 1024, 1048576, 1073741824 and instead of 'k' 'M' and 'G' they use 'ki', 'Mi', 'Gi' etc.
I never did really work how how you're supposed to pronounce them though, the 'i' doesn't roll off the tongue so easily at the 'o'.
I get 1.80 IIRC on my NTFS 2Tb drives after format or thereabouts.
There will always be some overhead but ten percent (200GBytes) sounds a bit steep! Just checked on the wife's 1T Movie drive and the overhead is about 1.6%. The filesystem is ext3.