Assumed Temp
Imbracablecrunk , there isnt any minimum percentage specified as to assumed being more than actual . You can feed anything higher than actual , the FMC will take it but may actually not reduce any thrust beyond the flat rating of the engine . You are gauranteed to get performance of 30c even with a assumed lesser than that and yes it is possible to feed assumed lesser than 30c , although it may not be of any real use . The only restriction that we use in our company is , not to do an assumed temp method if the difference between the ATOW and the limit weight is less than 500 kgs .