UCC28951: Power calculation in application Information section.

Hello. Have some questions about calculation of power in in datasheet's typical application section on equations 60 and 96.   For power losses used formula Pbudget= Pbudget-4*Pqa=29.7 W, where Pqa is power dissapated on one transistor. Since our converter works as PSFB only 2 of 4 transistor could be in "ON" state simultaneously, this means, that only half time of switching period two trnsistors are in "ON" state and 2 are in "OFF" stete. The power dissapation on trinsistors, that's in "ON" state is I^2*2Rds_on (roughly), on two tranthistors, that in off state  power dissapation is 0. In the next period, transistors were swapd and now other two is conducting. The avarege power dissapated on the transistors for full period (first two plus other two) are equeal to (I^2*2*Rds_on+0+I^2*2Rds_on+0)/2=(2I^2*4Rds(on))/2=I^2*2Rds_on. Why the coefficientwere in formula 60 given at 4. Same situation with the diodes or FETs on output. only one FET is on in half of the piriod so the avarge power on the diode in this period will be 2 times less, arent it?