I think if you have had 3 promotions and different responsibilities the space in your resume will be much more valuable with these, so ignore your internships. Remember b-school resumes are more about showing your leadership and stuff like that...I know that my resume for schools looked drastically different than my technical engineer resume.
If your internships were in the industry you want to go into but you dont currently work in it then you can talk about it in essays if it fits. If you work in that industry then what you do this year is far more important than what you did several summers ago for a few months.
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Kellogg Class of 2010...still active and willing to help. However, I do not do profile reviews, don't offer predictions on chances and am far to busy to review essays, so save the energy of writing me a PM seeking help for these. If I don't respond to a PM that is not one of the previously mentioned trash can destined messages, please don't take it personally I get so many messages I have a hard to responding to most. The more interesting, compelling, or humorous you message the more likely I am to respond.