Why would Phal leaves get smaller?

[NewLeaf]

Hi All!
I have a neat little mottled leaved hybrid phal I have had for a few years.

I recently started running out of room so out of necessity started trying new potting situations for some of the "leafier" orchids. This phal was put into a small teracotta container with holes for roots, basically mounted then hung in my shower window. (an old tea light oil burner)

To say it took a new lease on life is an understatement. I've been trying to find more containers to move all my phals but haven't found more thus far.

High humidity, diffuse bright light, roots and leaves coming out gangbusters since the move about 3 months ago.(4th new leaf starting since)

Its odd though the new leaves are about half to a third the size of the old ones. They seem more stiff and erect, mottling is increased with more white so I can only assume this is a change for the better but why would the leaves get so much smaller?

My only thought is it needs less leaf to collect the same amount of photosynthesis. Would that be a good theory or is there something else to explain the change?