I am not 100% familiar on all different pricing points at different locations, but speaking from a South African point of sale, you will usually find little monetary difference between saver and flex fares ( not including flex plus). I personally will on reasonable grounds always select the flex fare due to the better flexibility/miles. I do know for a fact that the difference between saver and flex from someone starting their journey in Zurich is a big gap, our flex plus fares down here in Cape Town would price out as their saver fares - if that makes sense.