This paper reports on the use of program slicing concepts and partial execution tracing at Adobe Analytics to address a major limitation of differential testing — namely, how to deal with the large numbers of differences typically produced by this regression testing technique. Manual verification, typically used to verify detected differences, is tedious, time-consuming and error-prone. This severely limits the volume of testing that can be done and thereby reduces adoption of differential testing. It is hoped that, by sharing this experience, researchers with expertise in program slicing might be motivated to help solve some of the issues and limitations encountered during this novel application of slicing to a real-world industrial problem.