Because of the log term in Beer's law the error in concentration for a given error in the absorbance measurement increases at either end of the absorbance range.
At low concentration a small absolute error can be a large relative arror.
At high concentration a small error on transmission, which is what the instrument actually reads, corresponds to a large error in concentration.
The 1 to 2% accuracy can be expected between absorbance readings of 0.1 and 1.0.
The highest accuracy is found between 0.3 and 0.4 absorbance.