> I'm guessing they know a lot about their costs, and you know very little.

I'm curious what makes you believe the OP doesn't know about cost? They might be director-level at a large tech company with 20+ years experience for all you know...

> There's little value in insulting the team members like this.

I'd argue it's not insulting to question a claim (i.e. 'we saved $6MM') that is offered with little explanation.