Different unit rates for same provider on different comparison sites

Friday_Girl

I am new to these price comparison sites, so can someone please explain to me why the unit rates for both gas and electricity can differ between the comparision sites for the same tariff?
I have been looking at: "Scottish Power Online Energy Saver 9"

UK Power uses an annual figure and quotes:
gas: 3.1771p for the first 4572kWh and 2.2705p for the rest.
electricity: 14.139p for the first 900kWh and 9.7467p for the rest.

Energy Helpline site for the same "Scottish Power Online Energy Saver 9" uses a 1/4ly figure (multiply by 4 to give annual as above), however it quotes:
gas: 3.336p for the first 1143kWh and 2.384p for the rest.
electricity: 14.846 for the first 225kWh and 10.234 for the rest.

How can exactly the same tariff from Scottish Power have two different pricing structures from different comparison sites? I thought the same tariff would carry the same unit rate regardless.

stewie_griffin

UK Power is the listing prices before VAT and Energy Helpline after VAT. That would be my educated guess anyway

Friday_Girl

Brilliant, thanks Stewie, I see it says that quite clearly in brackets underneath - but only now you have pointed it out!!