The reason there are multiple versions of this by-law is that the “model” by-laws provided by Fair Trading are there as a guide for new strata schemes, to be adopted automatically only if the new strata scheme fails to agree on its own rules.
Theoretically, every strata scheme should have its own by-laws that are largely the same but differ when it comes to the specific needs of that scheme.
Many new schemes adopt the model by-laws to begin with, then add their own as time goes on. Also, periodically, Fair Trading updates the regulations and changes the model by-laws. Frankly, i am surpoprised you have only found two variations.