Yes it's on the spectrum. We live in Germany, where pdd-nos is called 'atypical autism'. Ds2 has been given a dx of that, although I am certain he has AS like ds1. Will have him re-assessed when he's a little bit older (he's 3.10).
I think it is one of the things that will disappear with the new criteria for diagnosis. Aspergers is also going. Everyone will be given an ASD diagnosis and then it will be decided what level they are. I think you can google it or someone might come along who can explain it better than me