Hi,
a) importance for diffentiation is that the level of challenge within a curriculum needs to match/meet the child's needs, extend learning and support their stage of development. If expectations are too high the opportunity to fail is a real possibility, too low and the child fails to gain any benefit from the activity/curriculum area.
The National Curriculum on Autism.org.uk
b) by taking a personalised, individual approach to learning a setting can plan appropriate activities that meet that individual child's unique needs. The way a setting assesses each child and ensures that the child is a truly active part of that assessment process the more likely it is that the learning provision will meet, fulfil and extend their learning and development.
Hth xx