Will advanced organisms be the same as complex organisms? Why?

Yes. Complexity in design will increase over evolutionary time. So the organisms which are more recently developed (younger organisms) will be more advanced than the older organisms, who have evolved earlier. In the younger organisms, there is an accumulation of changes in body design that allow the organism possessing them to survive better. The characteristics that came into existence later are more advanced than characteristics that existed earlier. The younger organisms possess more advanced features for better survival and these advanced features are more complex than those present in earlier evolved organisms.