If you think it's that easy, just do a self experiment trying the QF pattern at home and then try and do a complicated task that requires brain processing. Then remember you have never left your own timezone and have slept in your own bed.
Don’t forget to add in all the other factors that further exaerbate the impact e.g. poor nutrition (airline food), confined space, partly recycled / filtered air (with higher concentrations of atmospheric pathogens), elevated ambient noise, anxiety etc.