I would need a letter from an engineer before they would even consider letting me use clause 5, so it isn't like just anyone can cherry pick the loads.
You have an existing kitchen so you should be able to look at their power bills to get the demand for the previous year. (75 kva plus 15 kw is 90 kva, not 112.5 kva) I assume you aren't looking at clause 8 for a reason. Is that reason, because 90 amp overcurrent x 600 volts x 1.732 = 93.5 kw?
Maybe you want to reconsider what "special loads" you are adding to your calculation under 8-210.
Could any of the new equipment be changed to 600 volts to avoid the transformer?
How about adding a new 15 kva xfrmr and a new panel for the new loads?
