pelihu
Funny, this seems to be a great example of jargon.
The terms "stakeholder", "sponsor", "champion", VOC (Voice of customer), ICA (interim containment action), SIT (structured invertive thinking), KTS (knowledge-transfer sessions), NGT (nominal group technique), CRM (customer relationship management), CODND (cost of doing nothing different), CTC (critical to cost), SME (subject matter experts), DSO (days sales outstanding), DR/FR (functional/design requirement) are great examples of jargon.
"Internal customer" is not.
You are writing a application for
business school admissions, and not for a retard faction.
There is nothing wrong with talking about your "change management" skills and using "internal customers" as an example. In fact, admissions will be looking for a similar demonstration of your general management aptitude.