That’s a single narrow example and does not accurately account for the taxpayer cost of doing this.
When it’s reported that the government estimates the cost to be 1.2 million (and that estimate was as of some date back in June - source: en.as.com/…/missing-titan-submarine-how-much-does… ) I understand that to mean over and above what their daily/weekly/monthly/quarterly/yearly predictable/normal expenses are.