Why does the Torah repeat the weight of the individual Keilim?
Rashi: To teach us that the weight was in Shiklei ha'Kodesh, 1 which it did not mention earlier.
Which is double the equivalent Chulin weight.
Why does the Torah see fit to state the total weight of each silver dish (130 Shekel) and each golden bowl (70 Shekel) that the Nesi'im donated?
Rashi and Ramban: To teach us the degree of accuracy of the weight of the Keilim of the Mishkan
Ramban (citing the Sifri): This is not due (not to a miracle, but) to the high quality of the gold, which had been smelted many times, leaving no dross.