Oggers, drift down speed change from the FMC is a very minor issue compared to wanting to know from the FMC what the drift down and OEI altitude capability is. Himalayas, N America, Iran etc. Boeing have expressed an aerodynamic degradation in terms of weight because that’s simple but it is still an aerodynamic problem and as such having a slightly higher speed from the FMC would be entirely correct and conservative when dealing with aerodynamic degrade issues.