Dont know who is seeing it but we get more buyer calls.

SEO is a targeted effort whose general direction is typically determined by what you want. You could definitely rank better for buyer or seller leads by choosing keywords and having a solid strategy for ranking well in search engines for them. For example: in your site's content would you choose to concentrate on the search phrase "homes for sale in _____" or "sell a home in _____"?

Everything depends on your target.  Know you target and write topics for them and that is what you are optimizing for.

It can be done for buyer, seller or both.  That being said, many on here have found it easier to find online leads for buyers. 

I suspect it depends on the types of things you post.

Since I fish exclusively for sellers the results are as expected.

Sellers 15 to 1.