"The overall sample size of 10 parts x 3 repeated readings yields 30 total measurements. The difference in precision of the dispersion estimate for 3 repeated readings is not substantially better than for 2 repeated readings. If we use 2 repeated readings we can increase the number of parts to 30 and maintaining the same number of overall measurements while improving the informative value of the study."
10x3 = 30
30x2 = 60
You say it maintains the same number of overall measurements but I'm not understanding how that is possible.