Is there any practical difference between the various assessment methods?

Hi Everyone,

I was diagnosed about 6 months and the one thing I get really confused by is the lack of consistent approach to diagnosis and the methods used.

My diagnosis consisted of 2 parts, ADOS performed by a speech and language therapist and ADI by a psychiatrist - my wife was my informant, 

On my assessment report it says that to get a successful clinical Autism diagnosis you must meet the criteria of both ADI and ADOS and the assessment must be carried out by a multi discipline assessment team with all disciplines being in agreement. Since my diagnosis I have heard from other Autistic People about their diagnosis process and confused how other clinics (including some NHS trusts) assess with only a single psychologist using ADI style questioning (i am actually really jealous about this as I found ADOS very stressful and left me burnt out for about a week). I wonder if anyone can offer an explanation for the differing requirements for successful assessment? It was suggested to me that it might be because my assessment covers both NICE and DSM requirements  but not sure if this is correct or not?

Also wondering if there was impact on support when receiving differing diagnosis. I do know someone in my Autism support group that was refused by Access to work support for reasonable adjustments when starting a new job. Their Autism assessment was performed by the NHS and appears it wasn't accepted as sufficient.

i get the feeling it can be a bit of a lottery how the assessment and follow up support process plays out, but its one of the things that really keeps nagging at me and won't go away until I have recieved an explanation, so really hope some one can shed some light on it :-)