Different ancestral alleles for same snp ID coming from different batch ID, same build

Question

[Mr Locuace]

Hello, I am new in the evolutionary genomics field. For getting ancestral alleles I have followed the instructions given here:

http://www.ncbi.nlm.nih.gov/sites/books/NBK44409/

However, when looking into the "SNPAncestralAllele.bcp.gz" file (GRCh37p13), I notice that for some specific SNPs (snp ID) there are batch IDs indicating different ancestral alleles, for instance snp IDs 915:

snp ID/ancest allele/batch ID
915    4    1050983
915    4    1052591
915    7    1061836

In these cases, should I consider the ancestral alleles with batch ID of higher value? Are those more updated?