After reading this I can understand why. Mental disorders are not something you can fit into a distinct mold. They all have variations and degrees of effect and many are mixed in the people that have them. For example, it's possible to have Asperger's and Bipolar disorder at the same time. How do you distinguish them? That is what your doctor is supposed to be for. There are long trusted tests that can be administered and very long questionnaires that can help decipher. Specialists have been using these for years.
This further supports my belief that the key is not the DSM, rather your doctor. Your doctor has the final say and write the proper insurance codes to get you the support (meds, etc.) you need. No matter what they write in that DSM, the DSM is not your doctor.
Since the recent suggested changes, I've seen people worried about losing their diagnosis or having their diagnosis messed up in general. I literally have had people say to me that they need to worry about avoiding re-diagnosis. Well, here's the thing, don't accept it. You know your child better than anyone, you've researched the condition in and out (I hope) and have a good rapport with your doctor (I hope) and you can stick with what you know. The reality of your conditions or your child's conditions don't change just because a book says so. Talk to your doctor about your worries and that you want to make sure your child gets the support they need.