Im talking about the service conductors I to the meter. Not the service drop conductors. Sorry fo the confusion
Service drop is a specific term in NEC, but thanks for clearing up what you are asking about.
310.15(B)(7) only applies to conductors supplying a single dwelling.
230.42 only requires these conductors to be sized to the calculated load.
230.90(A) exception 3 will allow overcurrent protection to exceed the conductor ampacity when there is 2-6 service disconnecting means and the calculated load is no more than the conductor ampacity.
Anything that exceeds the calculated load is design decision, NEC is met if that conductor has ampacity of the calculated load or more.
If you want to allow more capacity then calculated load, running parallel 4/0 seems to be a pretty common choice for such a situation, cost of material as well as easier to handle than 500kcmil+ conductors are major players in this decision.