Many people teach that Fuji films, especially Velvia 50, should be overexposed by 1/3 stop.

In addition, many people teach that Fuji films should be overDEVELOPED. They give different extensions to first developer time. Sometimes it's much more than 1/3 stop push. The official instructions doesn't say anything about this; E6 is E6, a standard process.

And probably, if your lab uses longer FD time for Fuji films, then I wouldn't overexpose.

Is there any official truth concerning overexposure or overdeveloping, by Fuji?