peanut storage facility load calculation

[Atm]

Thank you all for your help.

1. Is the approach to this load calculation correct?

2. Is 230.90 (A) Exception No 1 applied correctly?

Additional information:

service 480Y/277v four wire
480/120-240v single phase step down transformer

 

[Atm]

I see that if I correctly apply 430.63 as instructed to do by 230.90 (A) Exception No 1 I would:

Add the sum of the other loads 13 amps to the rating permitted by 430.62

So 13 amps plus a 250 A device (250% times 52 FLC of largest motor is 150 amp device plus FLC of other motors in the group 108 amps is a 250 device per 430.62) yields a minimum rating of 263 amps.

If this is so and I have not made any errors, does this mean a 300 amp overcurrent protective device inverse time breaker is permitted to protect a set of 250 kcmil service entrance conductors?