You are not the only one who asked the 400C question. Trust me, it does! and in a matter of minutes!
I used a round type barbecue recently, a bit like the lower section of your Nipoori oven. I measured temperatures of up to 250C at grille level, just a few inches above the charcoal. If I raised the temperature probe further from the charcoal, the temperature fell away quickly, down to perhaps 150C. I covered the barbecue too, a bit like your tandoor hood. The temperatures I measured are similar to those recorded for charcoal barbecues on various websites like this one:
http://www.kingsgrill.com/innerpages/comparisons.htmThey state temperatures of up to about 440F which is mid 200s Centigrade, like I found. I really will be amazed if your Nipoori oven can somehow get the temperature up to 300C or 400C. I still don't understand how it's achieved with a commercial tandoor. On the one hand, tikkas and naans cook quickly so it must be hot but, at temperatures above 300C I don't see how anyone can reach into the tandoor with their arm, even for a few seconds.