This image shows how far airborne tholin aerosols are blown by Pluto winds.
I don't know the exact scale but this wind blown tholin extends about 50 miles.
Tholins have to be heavier than the atmosphere else they wouldn't fall and deposit all over the place.
The atmosphere and wind must be dense and strong enough to migrate aerosol particulates many miles.
Sastrugi are just one other example of the winds density and strength as it carves features into the snow at Burney, makes ripples near the softer warmer troughs of nitrogen on SP and as it carries tholin aerosols for miles.
I suspect Pluto's atmosphere and winds are thicker and stronger than NASA comprehends.
At the very least, I think its safe to say sublimation is not the only way to interpret the many bowl shaped cups and ripples on SP.