Boeing tend to build aircraft as the customer wants.
In a previous life, we used to start 2 at a time (CF6s) at any alt or temp - with one pack running as well. We started 1 and 2 together if pushing back to the right (as viewed by the tug driver) and 3 and 4 together to the left. This is because the push would come to a halt if you tried to start the two engines on the outboard side of the turn. We would defeat the tug!