OG was much higher than expected...

Well, I just finished up brewing my biggest beer to date! It definitely pushed my brewing problem solving skills and my minimal equipment to the max! Anyway, it's a strong scotch ale and I have some oak cubes sitting in a bottle of Maker's Mark that I'll combine with the brew in secondary in a few weeks! I plan to bottle and maybe open the first one around Christmas time. Needless to say, I'm very excited about this one!

There's the background, and here's what I'm curious about. My projected OG was around 1.123 with an efficiency of 75%. Yes, I know, that's high already. But somehow I managed to record my OG at 1.146! I triple checked the reading and it's correct. Anyone know how this can happen?

Here's my recipe if it matters:

http://hopville.com/recipe/589294/scottish-export-80---recipes/kilt-remover

1.146?? Holy hell! I've never even come close to that.

The extract in the partial mash will give you 100% efficiency compared to the grains. Perhaps the brew calculus tool of hopville assumed 75% efficiency for every fermentable underestimating the OG. That would be my guess.