Ouch, IdleHands! First of all, I'm AS myself, and once diagnosed was promptly medically retired because my 'employers' couldn't cope with the implications. The cost of my MBTI training was paid for by a charity, and in recognition of that I have never accepted a penny for any work I have done with this qualification in the 15 years since I did the (160 hours teaching and study, plus exam and supervised practicals) training. 'I' don't have a 'version' of MBTI - my training helped me to orient myself with the experience of the professional community that has been using MBTI for over 50 years. Millions of people world-wide have taken the indicator over that period, so there is a mountain of evidential data to support it's conclusions.
The trouble is, alongside the good stuff, the internet is awash with misleading stuff about MBTI - like the idea that it is a 'test that will tell you your personality type'. One person will recognise themselves in the letters that emerge from their answers - but may feel that this is somehow telling them how they need to live to be happy and fulfilled! Another may feel they are completely different from the personality their letters describe - so rubbish the whole thing on the spot, unaware that there are further stages and subtleties to explore to get to the real answers. It's because I do believe MBTI is valid and useful that I want to defend it in the face of home-made versions of varying quality.
MBTI and autism, now there's an interesting and complex subject, about which there has been very little writing or research. My working theory is this: that the MBTI properly used can identify the core personality type of a person with autism. (There is a version for work with children -MMTIC- might help with those who are lower functioning?) I think you'd need a larger randomised sample before safely claiming that 'most autistics are INTJ'. It seems to me that the presence of autism can slew the initial results from the questionnaire, but one can compensate for that in the 'best fit exercise' which is the following stage of the full process. Autism seems to make it harder for some types to access their personality strengths, and can also exacerbate the stresses arising from the 'less preferred side' of one's personality. MBTI knowledge can help autistic people to anticipate or even avoid 'meltdowns'.
I could say much more - but Aspies are famous for their ability to bore on their favourite subjects! But if I can answer a question, then I will!