In which case, what does paragraph A.1.43 mean? For most monitoring the Control Limit is the only limit that exists to be measured against so reporting to 2 d.p would be correct surely?
A1.43 The concentration result must be calculated and recorded correct to the appropriate
number of decimal places, depending on the reasons for sampling and the decision being made;
eg to determine whether the 0.1 f/ml control limit is exceeded, calculate and report to 2 decimal
places. For the clearance indicator where the fibre level should be less than 0.010 f/ml, calculate
and report the result to 3 decimal places.