Interest only question

Hi all,

Just have a question in regards to interest only loans. As I understood, you are effectively only paying the interest payments, so the loan amount should remain static? The first repayment for my IP has come out and there is a difference between the repayment and interest charged, meaning my loan amount is increasing ($60 odd).

Is this just due to some interest rate charges?
It is because some months have 30 days and others have 31 (or 28 & 29 for the pedants). Then sometimes your due date falls on a non-business day and they don't get your payment until Monday (instead of Saturday for example).

It all works out in the wash.
Propertunity sums it up nicely. As always :)
The worst months are the 31 day months during which the 31st is a Friday, so the payment may be processed on a Monday night and include 2-3 days extra interest. Sure it all comes out in the wash, but eating 2 minute noodles for a month until the next round of interest isn't much fun :(