You probably have an inaccurate primary bucket as most of them are off a little and added a tadmore water. You can add a little sugar to bring it back up if you want. I typically add 4 lbs of sugar to these kits to bring the finished abv up to around 10 1/2 -11 and it works awesome but beware this voids the warranty.
[measure 23 litres (6 US gallons) of water into]
This is on the directions but silly me did NOT do that so I will take your advice..
I had to laugh here at myself because I have in the past told my hubby about not doing things by the directions!!!!!!!! Dang = hate when this comes back on myself. LOL