Thanks.
Flex is possible if it is between Tmaxflex and both Tref and OAT.
I am sure TOGA is mandatory if Tflex less than Tref and more than Toat. But what a stupid am I -if Tflex is less than even Toat are we allowed to use TOGA (if RTOW permits) or should we find other aircond. conf. or RW and so on.