New renewed, Oct bill for Nov all wrong

[#1]

Just got my Oct Bill.
I renewed contract to start on 1st Oct @ £22.99
Previous @ £24.60 (to 18th Oct) which is as you say we pay a month in Advance so is covered.
So why is my Bill £30.25?
I might be old but according to my calculations the Bill should be Less than the previous £24.60
Please someone clarify!!!

[#2]

This will be rectified on the following bill. This is due to the new contract starting on the same day as your billing date, it doesn't always match up when the discount get added to when the bill is produced.