Power Dissipation of Main switch in Boost PWM Supply

In the Linear Tech data sheet for the LT1700 :

on page 9.

the formula for the I^2R losses in the main switching FET are given as

DF*(I(out))^2 * Rdson

I think that for the MAIN FET switch, not the synchronous rectifier FET) the I (current) term should be the input current not the output current???

i.e.

DF*(I(in)^2) * Rdson

am I missing something??

thanks Mark