Why does the NWT give preference to the word "tradition" at 2 Thess. 3:6 and at 2 Thess. 2:15?

In 2 Thessalonians 3:6 the Moffatt translation reads in part: " instead of following the rule you received from us." Other versions read "direction," "commandments," "teaching," and " instruction". Why does the New World Translation give preference to the word "tradition" in this text as also at 2 Thessalonians 2:15?

The New World Translation endeavors to be consistent in its renderings. In keeping with the rule noted in the Foreword of the New World Translation of the Christian Greek Scriptures ,as far as possible it uses just one English word to render one original Greek word into English. The Greek word here is par'edosis, which has the thought of a transmitted precept. It is the same word as is used at Matthew 15:6, where Jesus told his religious opposers that they made the Word of God void by reason of their tradition. While the word "tradition" is frequently used in contrast to Bible truth handed down in writing, it is not limited to such precepts. The use of the word here as well as at 2 Thessalonians 2:15 shows that there is a valid tradition by the apostles, which tradition was committed to writing under inspiration. This, of course, differs from uninspired tradition, tradition that invalidates God's Word.

Thus the New World Translation, in rendering par'edosis "tradition" at 2 Thessalonians 2:15 and 2Th 3:6, has remained faithful to its rule. It has not let the opprobrium usually attached to the term "tradition" by sincere and enlightened Bible students cause it to use another word in this and its related text. This is in contrast to the Diaglott, which has been so influenced. In the interlinear translation It uses the word "tradition" in both verses, but in its English text it chose to use the word "instruction." The Revised Standard Version, however, uses the word "tradition," even as does the American Standard Version. - Taken from The Watchtower, Question from Readers, May 1st, 1961, pp.287/8.