Just to note: you don't specifically buy peak and off-peak units, just a total and they are called off by any use. So if you use less peak bandwidth in a given month, you can make up the difference with off-peak use, and vice versa. You'd buy three units, not two peak and one off-peak (the calculator on the website displays it that way as it needs to ask you for the two figures, not because the bandwidth use comes out of two separate pots). You could use 1 peak and 2 off this month, 1.5p/1.5o next, 0.3p/2.7o the next, and so on. If you only use a total of, say, 2.2 this month, the extra 0.8 gets added to next month's quota.
It is effectively counted to the granularity of a byte. A 1000 bytes downloaded uses 0.0000004 units in peak time, 0.00000002 off peak, and 0.000000001 in the really cheap bit between 0200 and 0600 (I've worked those figures out in millions not 1024*1024, they might be counting in GiB not GB (I've not checked) in which case it is ~4.8% better: 0.0000003814697265625/byte rather than 0.0000004 in peak time for example). As with idnet, upstream bandwidth is not currently counted against anything.
If you use very little bandwidth in the working day period on weekdays, as is my case, this works out cheap compared to some other ISPs offerings. And in those months where i do need a chunk more daytime bandwidth the flexibility (units being generic, the month-to-month carry-over/-under) means I don't really have to worry about it. If you regularly use a lot of daytime bandwidth, it can work out quite expensive of course.
Current Line: Andrews & Arnold (AAISP) via 80/20 FTTC, getting close to the full rate both ways, joined July 2011, upgraded from 40/10 to 80/20 May 2012.
Previous setup: Be Pro with UploadPlus (ADSL2+, AnnexM), 12ish Mbit down, 1.6 up, happy customer for ~2.5 years.
Edited by dspillett (Thu 19-Jul-12 20:36:20)