Excel 2008 Gas n Electric bills

Hi
I am fairly new to Excell and I am trying to get a grip on my gas n electric bills. My problem is in creating a formula to convert the info I have into the final bill.
The info I have is -: days of use, amount of G n E used, standing charge, price/unit and discounts applicable.
For simplicity I have converted them all into a rate per day and £GB.
I tried the following formula

:-(standing charge per day * days used)+(cost per KWH * No.of KWH used) - (discounts * days used) / (100) * (94)

This last one is to account for a direct debit 6% discount. I used cell address for things like No of days usage and KWHs used in the period. The values in these cells have themselves been calculated via a formula from other info. The results I get seem to be a constant variable which indicates that I am doing it wrong.
I am obviously doing something wrong Any help would be appreciated An many thanks in advance

The premise of the calculation is fine, can you post what you're working with so we can see what's actually happening in the sheet?

Thanks

https://www.dropbox.com/s/jyh1rnvhy1...ERIMENTAL.xlsb

Here's a link to the Excel sheet on my dropbox.
Thanks again.