UKM size in the SMIME Freeware Library v1.8

I have been testing our product with the latest SFL version. More
specifically, I have performed tests using the Diffie-Hellman key agreement
method. From the RFC (2631), the size of partyAInfo contained in the
OtherInfo sequence must be 512 bits in size. However, the SFL produces
keying material with partyAInfo set to 128 bytes. Should this not be 64
bytes? Perhaps I am missing something.

Thanks
Ahmed