many houses fell 30% since 2007

Many areas and properties that were hot in 2007 have been hammered with 30% falls.
That equates to the 'some rose 50%' since a 33% fall will take those few 50% rise properties back to where they started in 2007.

I doubt many homes that rose 50% after 2007 are anywhere near that level now. Most of them will be back where they started in this extreme buyers market and soon they will be below that as they play catch up.