I offered my comments about the IAS on another thread, but thought I'd repeat my thoughts here. The IAS is a great tool, IMHO, for facilitating the discussion necessary between parents, teachers, administrators and even the student (when age appropriate) regarding acceleration. I think that if you use it as intended, to view ALL the components necessary for a successful grade skip, then it can be very helpful regardless of a child's weaker areas or 2E considerations.

In fact, I think that in cases like this, the IAS could actually lead the team to a discussion of how to meet those needs, in light of all the other components pointing to grade acceleration being appropriate. What better way to get people to recognize that there is only one thing holding the child back (acheivement), and then facilitate a discussion of how to remediate that need? Wouldn't scoring well on everything else on the IAS indicate that the ONE area of need should be addressed?
At least, that's how I see the IAS being used.

If you have interest in using the IAS and want to know more about it, check out this article on Hoagie's Page:
http://www.hoagiesgifted.org/iowa_accel_scale.htm

And if you'd like to speak directly to a co-author, I'll bet you could reach one at the Belin-Blank Center:
http://www.education.uiowa.edu/belinblank/bbc/staff.asp

Both Susan Assouline and Nicholas Colangelo work at the center.