Key question: When you open a document containing tracked changes, what is the Display Mode set to?
The Display Mode is controlled by the installation of Word that is opening the document, it isn't a document property. In all versions of Word for Mac the default is All Markup (or Final Showing Markup, depending on version). There is no Preference or Setting that will change it.
Traditionally, Word for Windows has been the same way for a number of reasons including the one you mentioned. However, that changed in Word 2013. It now defaults to Simple Markup, ostensibly to make the document appear 'cleaner'. That has persisted into Word 2016 for Windows, as well. Please see this Microsoft hype on it: Track changes in Word - Word
It sounds like you're exchanging documents with PC users. There is no way for you to control this on their systems... They need to be better informed about the new behavior of the software they're using.