TOGA FLEX TAKEOFF NOT THE SAME....
Toga limit for both eng. take off is 5 min n with SE OPS it's 10 min, now also with this u have ur takeoff temp limit for both eggs given, eg.
CFM ENG MAX EGT FOR TAKE OFF IS 950 , but using MCT IS 915 , now the 10 min toga power on SE ops and 5 min on both eng take off does apply but also bearing in mind the max eng EGT ie 950, but when u use MCT ITS NOT TIME LIMITED But EGT LIMITED SUNCE U KEEP MONITORING THE EGT SO AS TO NOT GO ABOVE EGT LIMIT OF 915 ,hence toga and flex take off have their temp and time limitations for both eng ops and SE OPS,
TOGA TAKEOFF AND FLEX TO ARE NOT THE SAME, TOGA TAKE OFF WILL REDUCE LONG TERM ENG LIFE DRASTICALLY, WHERE AS FLEX TO WILL INCREASE ENG LIFE , AND ALSO REDUCE ENG MAINTAINANCE COST.
just like mentioned earlier by SQUAK7600, the rate of damage is non linear hence its becomes difficult to actually check up how much damage has occurred over a give period of eng hours.
MOSTLY FLEX TAKE OFF IS USED FOR EVERYDAY OPS UNLESS IT'S NOT POSSIBLE TO EXECUTE A FLEX TAKEOFF DUE TO PERFORMANCE LIMITATIONS FOR A GIVEN FLIGHT, THUS LEADING TO A TOGA TAKEOFF. in my company we Mohave to make a pilot report of toga take off has been used instead of a flex takeoff, post flight in the post Flt report form, so that mx crew have a record of it , just to keep monitor eng life.
Well hope this give u a little better idea of flex and toga not being the same,