My question is about the transformation of WHOQOL-BREF scores to WHOQOL-100. In the guideline provided by WHO, we can transform the raw score by using a calculation formula as well as using a Table provided for transformation. However, these two methods give different transformed scores. For example, if the raw score of Domain 1 (Physical) is 8, the transformed score would be 3.57. But in the table (Method for converting raw scores to transformed scores, provided by WHO), the transformed score is 6. Similarly, the transformed score for a raw score of 20 in the Psychological domain will be 58.33, which is provided as 56 in the Table. Such discrepancies can be observed in all scores across all the domains.
Why there is a difference and which one is correct? Am I missing something here?