It depends what you mean by busy hour… Typically, you would average BH traffic over a few days to decide what ‘weekly’ BH traffic (for dimensioning & projecting purposes) is… Some enlightened operators even use ‘bouncing busy hour’ to dimension resources.
If you don’t average, then you end up building capacity for the peak-of-peaks and dimensioning for non-typical spikes in demand. Which means your congestion is unecessarily low, but more importantly, you’ve got excessive network capacity (transcievers, transmission links, line cards, switching capcity, trunks etc) that only get used for about 72 seconds a week (if you have 2% blocking for the BH).
In India, as I understand it, with the huge increases in subscribers/traffic, you’d be well advised to ignore Erlang tables and put a load of capacity in anyway – it’ll save you having to go back 2 weeks later and add new radios!
Erlang is still theory and nobody told the callers they have to call with a Poisson distribution and not retry if they don’t get through…