Oh i'm sure what I put in the calculator was correct.. I just must have picked up the wrong bottle when mixing. It can become a little confusing when mixing a whole lot in one go. I get most of my nic from Molin shop in Poland and their stuff comes in thick opaque plastic bottles with only a slight difference in a patch of colour in the label. It becomes even more confusing when you have a lot of similar bottles on the table because the 100 ml EM I also get from them is also packed in an almost identical bottle. I don't put it past me having added more nic instead of the EM LOL... which is probably what happened.
Well at least here's another excuse for laughing at myself. 
ETA - you can't get 100mg nic anywhere in Europe.
ETA - you can't get 100mg nic anywhere in Europe.