1) A possible scenario could be as follows. Reuven has ten daughters and owns $100,000. Each daughter gets married one year after the one before. The first daughter receives a dowry of one tenth of the total sum, so she receives $10,000. The second daughter gets married a year later and receives one tenth of the remaining $90,000, so she gets $9,000. The third daughter marries the next year and receives one tenth of the remaining $81,000, so she gets $8,100. It continues like this until they are all married. There is still some money remaining from the original $100,000. This is divided equally between all ten sisters.

So it is not a question of when each one claimed, but since they are now all married and are coming to split up the remainder of the original $100,000, there is no reason to give any sister more than any other. When they were getting married, the daughter that gets married earlier gets more, but now that they are all married they are considered equal so they receive equally.

2) The Ran here in Nedarim writes very concisely and does not explain the situation in detail, but the Gemara in Kesuvos 68b states, at slightly greater length, that what is stated in the Beraisa, "v'Chozros v'Cholkos b'Shaveh," refers to a scenario where "Ba'u Kulam l'Hinasei k'Achas" -- "they all came at the same time to get married." It seems that this is what our Ran means when he writes, "sheb'Bas Achas Ba'u Litol" 00 "they came simultaneously to receive [their money]." Since they all come at the same time, it is logical that it is not fair to split unevenly.

Kol Tuv,

Dovid Bloom