>> Maybe it means "calendar days" (day intervals) rather than "business days"
違うみたい。
net 30 days は会計（決算？）の基本コンセプトみたい。
Take the case of another ABC company.
ABC makes a new widget.
They produce the widget at $0.75 a piece and sell it for $1.
They always keep 30 days supply in inventory
They always pay their bills promptly
They allow customers to pay in 30 days (net 30 days)
