A transformer can be loaded to 100% of its capacity but you;ll have to size the conductors and OCPD at 125% of the secondary full load current in order to take advantage of this. Note 2 to table 450.3(B) says you can have multiple circuit breakers on the secondary side, but they cannot total more than what a single breaker would be.
You are mis-reading 450.3.
A transformer is required to have a primary protective device rated at not more than 125%
unlessthere is secondary protection. So, if the 45kVA primary side is protected at not more than 67A, all secondary protection may be ignored.
But, the secondary conductors need to be protected under 240.21(C). I can envision this particular installation as being acceptable under 240.21(C)2, 3, or 6.
