One can discover great technical communication in the unlikeliest of places.
Here’s a sample from the bottom portion of a restaurant bill I came across recently:
Why oh why did someone not think of this sooner? My only quibble is that the terminology is inconsistent – the heading uses gratuity whereas the listed items use tip, but that’s a minor point.
This document saves the user the grief of having to manually calculate the tip. It considers the needs of the user and immediately fulfills them, like any great document should.