You might find some useful information here, in this brief interpretive guide:

http://riversidepublishing.com/products/cogAt/pdf/cogATshort.pdf

According to the HMH website, the range of index scores you report should have triggered a review of validity (both because of the diversity of scores, and because of the extreme nature of two of them). (See the interactive score interpretation page: http://riversidepublishing.com/products/group/cogat6/input.jsp)

This document lists the allowable accommodations, on pages 10-13. Also specifically says that CogAT is not an intelligence test (p. 64):

http://ed.sc.gov/agency/ac/Assessment/documents/SCTCM_13_Manual_FINAL.pdf

You would need a 504 for frequent breaks. No more than an hour of testing is supposed to be administered per day for primary-age examinees.

I imagine that the reason your school system insists on CogAT scores is to maintain a consistent policy and procedure for entry to GT programming. Note the GT CogAT may be the three-subtest screening version, and not the six- (gr K-2/K, 1, 2) or nine-subtest (gr 3-12/A-H) versions.

...pronounced like the long vowel and first letter of the alphabet...