Most of the price differences between Fannie Mae and Freddie Mac loans have gone away in the past 12 months. For years Fannie Mae did not add a price hit for detached condos, but Freddie Mac loans did. Today, the policies are aligned so that if the property is an attached condo, 20% down, it's .75 higher in fee. If the property is a detached condo, 20% down, there isn't a price hit.
Jumbo loan products vary so if you're looking at a unique bank product, not Agency paper, it's hard to tell what the true price might be when comparing attached vs detached pricing.
My .02c