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 need to state both the weight of each vessel and the total weight of all the vessels together?
Rashi: To teach us the degree of accuracy of the weight of the Keilim - there was no discrepancy between the sum of the individual weights, and when they weighed them all together. 1
See Sifsei Chachamim.
QUESTIONS ON RASHI
Rashi writes that the sum of the individual weights was the same as and when they weighed them all together. If this was a miracle, what was the reason for it; and if it was not, why does the Torah teach it?
Ramban (in Pasuk 2, citing the Sifri) and Moshav Zekeinim (in Pasuk 84): The Pasuk is teaching us that the gold of which the Keilim was manufactured was so pure that, after smelting it and making the Keilim, it did not weigh any less than before the smelting. Had they taken a piece of silver or gold and made a K'li out of it its weight would not have decreased 1 due to the fact that it been previously smelted many times. 2
Normally, one who gives to Hekdesh weighs on a balance scale with a Hechra (he gives extra, to make the Hekdesh go down and the weight go up). The total excess is greater if one weighs part at a time than if he weighs all at once. 3 Perhaps here they weighed precisely, without Hechra, due to the intents mentioned above (refer to 7:13:5:1-3, 7:13:6:1-5. - PF)
This Chidush applies even if they did not weigh all the Keilim together! Perhaps they weighed only before making each Kli, and at the end, all the Keilim together (PF)
Newer printings of the Ramban say 've'Lo Na'aseh bahen Neis' (no miracle was done with them). Moshav Zekeinim cites the Ramban like an early printing 've'Lo she'Na'aseh bahem Kach.' (PF)
This is why the Torah obligated weighing Kin'man Bosem for the anointing oil - half at a time (Refer to Sh'mos 30:23:5:1*), and a seller may not use weights that are larger than the custom, to minimize the number of weighings - Bava Basra 88b (PF).
