Practice was similar in my shop. Routine letters went out over a Division Chief's signature (equivalent probably of a lower-level VP or high mid-manager), with letters about policy (such as commenting on regulation development) over the Director's or a Deputy Director's signature. When signed by a DC or DD, one presumed that the general content & tone was checked with the higher level before signing, or that the person was familiar with the issue (a briefing paper usually had to accompany the letter) and agency policy regarding it. Something to an oversight or funding agency almost always was at least checked if not written by the legal or finance office, not some generic VP.

For a letter like the one discussed here, it would be reasonable to presume that it had been checked with the higher level and approved. That's standard practice. If this was a rogue letter, the person involved probably doesn't have a job anymore or shortly won't. That would be true whether or not it's a government agency.