A standard kit plus a kilo of additive will give an og of around 1.045. Making it to 22 litres won't make much difference to the og. You didn't accidently make it to 17 litres?
There could have been some malt extract stuck in the tap which gave you a false high og reading. Or your hydrometer is dodgy, try floating it in plain water, it should read 1.00. Or maybe the sg sample was hot and this gave a false high og.
The style guidelines for an IPA do have higher og's, but to achieve this, you need more malt extract and additives. Plus you need to add extra bitterness and hop flavour to balance the higher fg from using extra malt.