"Dave Liquorice"  writes:

> On Fri, 09 Oct 2009 22:49:25 +0100, Roger Lynn wrote:
>
>>> In my view a "unit" is an, immutable, fixed amount of something.
> Here 
>>> the amount of something (GB downloaded) varies with the time of
> day the 
>>> download happens. 
>> 
>> A unit is fixed - it represents UKP2.55+VAT. 
>
> Well yes, but ...
>
>> You get a varying number of GB per UKP2.55+VAT. 
>
> Which is arse about face compared to how everything(*) else is
> traded. You buy diesel at £/l, cheese at £/kg, gold at £/troy ounce,
> oil in $/barrel. ie the amount of the thing you are buying is fixed
> not the consideration.
>
> (*)I can't think of anything that is sold in "<unit>per£".

Just think back just a few years to the cost of telephone calls before
BT changed to per-second pricing. Calls were charged at a fixed cost
(4.2p ex VAT at the end) per "unit". The length of each unit depending
on the number you were calling and the time of day. This is directly
analogous the "unit" in the new A&A pricing. So there is a precedent for
this usage of the term "unit".