We had the same situation last year except DS7 was spending half his day in K (age appropriate) and the other half in 1st grade. When we wanted him to just skip to 2nd this year the 1st grade teacher thought that he should do first grade due to his social skills and the fact that he missed the morning portion of 1st grade each day and may have missed something important.
This came during a meeting when we discussed how the 1st grade work was still not close to challenge DS and meeting his needs!!
I totally feel your pain and can't even being to understand some of these teachers.
FYI: We did get the skip to 2nd for DS7 this year.
