coveln, the teacher's comments may be skewed in favor of the teacher's efforts to "close gaps" in the classroom (performance gaps, achievement gaps, excellence gaps) so that all students are recorded in the gradebook as learning, knowing, being "the same." Teachers and schools are increasingly rated/ranked on having no "gaps" in the classroom.

Closing gaps may consist of efforts to bring up the bottom.
Closing gaps may consist of efforts to cap growth at the top.
Demographics may play a role in determining whose growth to cap.
This old thread may be of interest, lend insight, and assure you that you are not alone.
- http://giftedissues.davidsongifted....245083/Grading_practices.html#Post245083