Yes koi official statement nahi hain but ye view unhi ka hai bcoz only railway officers have that much resource to make such calculations.
Of course this statement has zero official value but then your view has also,mine has also and iri also. But we do discuss upon it na.
Iri pe post wale 99% debates ki koi official value hoti hai. Wo to railway admin ko jo lagta hai jo Rm sochta hai wahi hota hai.