Dear Tassoss*
Thank you for your answer*
You've speculated yourself by understanding that Uncertainty value= 2% of true value* right? because it's unreasonable if accepted Uncertainty= 2 (It will be much more larger than true value) whether absence in the description of CRM's Certificate.

But I wonder* Is this the exactly rule for all CRM Certificate? Because in some cases when you calculate under percentage of true value and use exactly itself is reasonable in both cases. What is your decision at that case?