ibc 2006 wind load rooftop structures

huangyhg

ibc 2006 wind load rooftop structures
international building code, 2006 edition
section 6.5.15.1 states that the force on rooftop structures with an area less than 0.1*bh should be increased by a factor of 1.9 if located on a building less than 60' tall.
seems to me that if you were to plot the force on such a structure from 0 to 60' and continue to higher heights that the force would have a sifnificant drop between 60' and say 61'. does this make any sense? this entire section seem unclear to me.