they typically do if they have the excess land.Why pay for shoring if you don't have to? Often they use shoring if they front onto a new public road though. I imagine it's to avoid the city being particular about what kind of fill is used to backfill it since it will become their property.. if it remains undisturbed soil the city likely doesn't pay as much attention.They never did earth retention for Phase 1. Just dug wide. Saved a lot of time and money for both Phase 1 and 2.
I wonder , why other multi-building projects rarely do that ?