Shift meter box usually means you need to pull new main cables from meter box to your inside DB. If don’t want to pull, can extend the wires but not really recommended.
upgrade to 3 phase 63A is about 5k plus payable to SP. 3phase 100A is just under 10k. Your internal wiring cost is based on what your own electrician quote you.
when you upgrade, SP will put in new smart meter for you. No additional cost
as this is part of the fees you pay.
pub is another cost need to pay if you intend to shift the water meter as well