Franki, on your figures,
<Own ACFT weight : 85000 KG
Max Payload: 60000 KG
MZFW: 126000 KG>
The Max ZFW of 126k is the limit, therefore depending on configuration, the A/C weight may be light enough to allow up to 60k payload. With fewer seats/catering and in the lightest configuration, Boeing reckons that the max payload would be about 60k so that the limit of 126k is observed. I think what they are saying is the lightest possible ACFT weight is 66k. The fuel hasn't even entered the equation yet!