While I agree you should get IPSEA and SOS!SEN to look at the whole EHC plan, and Sections B and F are the most important; its still important to get the outcomes right - because if you don't have a particular outcome, then there is not likely to be a provision for it in F, and iirc, outcomes can't be appealed against?
I'd get all the SMART outcomes you want in Part A; the LA may ignore them, but at least you have tried. After all, if you want to argue for him to continue in education until he is 25 through the EHC plan, then there still need to be outcomes to be achieved. (For instance, if might be in your LA, that many young people with SEN leave school at 16, and only get 2 years funded in a FE college. As young people with SEN take longer to develop, you might want more than 2 years for him - the outcomes have to be framed to allow you to argue for more time in education. You could ask later, for more time in education, for a cooking course, which is a vital independence skill?)
As he is in Year 11, think about what you want him to achieve in adult life by way of - employment/meaningful activities, community participation, health, and independent living. Outcomes feed into those too - for instance, think about independent living skills, exercise for health, office skills or whatever he is likely to be heading towards in employment, what activities he might want to attend (and specify what social care he would need to enable him to attend, if relevant to him). I found outcomes were somewhat scarce in the assessment reports by the professionals, and what there were, were certainly not SMART. It was left to me and the LA to come up with most of the outcomes.
I went to another workshop by Ambitious About Autism recently, about the Care Act 2014. They recommended parents draw up a timetable of what support the young person (YP) needs to get through each day of the week, Monday to Sunday in term time; and another one for what the YP needs each day in a week of the school holidays or INSET days. This might be a bit OTT for someone with Aspergers, but this is just an example:
7 am 1:1 support for getting up, toileting, dressing and washing in the mornings
8 am 1:1 for getting breakfast, administering medication, getting ready for school, personal cleaning, help with shoes/coat
8.30 am 1:1 escort for taxi
9 am - 3.30 pm 2:1 or whatever support YP needs in school
3.30 pm 1:1 escort for taxi home
4 pm 1:1 for getting a snack after school
5 - 6.30 pm after school activities like Special needs drama - 1:1
7 pm 1:1 to supervise YP while someone else gets dinner
9 pm 1:1 to supervise showering, brushing teeth, getting ready for bed
10 pm 1:1 for bed routine
Sometimes waking nights - 1:1
You know better than Social Services just how much support he needs to get through all those tasks in daily life. Might as well analyse it now! It all sets the scene for what he might need, in FE college (especially if you have to think about specialist residential), and looking further into the future, supported living one day, by way of social care.