Educational placement MR VS AUTISM

[dorton78]

Questions regarding placement for my child MR VS Autism.

I have a 6 year old daughter who was diagnosed by her neurologist  around age 3 with PDD she also has Moebius syndrome which affects the 6th and 7th cranial nerves.  She is non verbal, developmentally delayed and shows many signs of Autism.   She has been attending  a PPCD program since age 3 and this year  is in a regular kindergarten class pending the outcome of Psychological/Autism evaluation.  The evaluation was completed and the outcome wasn’t what I expected.   She meets the Texas Education Agency eligibility criteria  as a student with mental retardation and not Autistic.   The outcome is said to be for educational placement.  In this school district there is 2 possible placements for children in special education- 1. Functional Academics (children with MR)  and 2nd. STM- Structured Teaching Model (specialized instruction in communication/behavior disorders in a highly structured classroom for children with Autism.  

The Gilliam Autism Rating Scale GARS 2- The evaluators gathered  information from 3 raters (parents, PPCD Teacher from last year and current Kindergarten teacher):  Here are the results/summary provided by the LSSP:
All three raters marked items such that the autism index fell within the “very likely” range for probability of autism. When reviewing the information on the GARS, the following behaviors from the Stereotyped Behaviors were marked as observed by majority of the raters: avoids establishing eye contact; stares at hands, objects, or items in the environment; whirls, turns in circles; makes high-pitched sounds; and flaps hands or fingers in front of face.  She clearly exhibits significant stereotypic behaviors and has been identified by her physician as having difficulty with sensory integration.  Most of the raters also identified the following characteristics from the Communication subscale: repeats words with sign; looks away or avoids looking at speaker when name is called; inappropriately answers questions about a statement; uses yes/no inappropriately.  Avery has a severe communication disorder which likely accounts for these characteristics.  The characteristics from the Social Interaction subscale identified by most raters were the following: avoids eye contact; does not imitate other people when imitation is required; withdraws, remains aloof in group situations, responds negatively or with temper tantrums when given directions.  Avery displays social deficits, which are not uncommon in children exhibiting global delays.
While she clearly displays numerous communication and behavior patterns often associated with an Autism Spectrum Disorder, many of these behaviors can also be attributed to her medical diagnosis, and her cognitive and developmental delays.

She also had an Autism Diagnostic Observation  Schedule (ADOS) assessment done and  was classified as likely within the range of an Autism Spectrum Disorder.

The question I have is why would they place a child who clearly is an Autistic child with severe speech impairment in a classroom placement for children with MR and not address the core problem and place her in an classroom that specializes in children with Autism?