Even though I'm late to the game, I'll submit in the hope that my answer will be useful in the future. The following may come off as cynical but it isn't meant that way - it's just my opinion on the purpose and intent of a corporate PR publication.
You mentioned (justifiable) concern that the revised headline is misleading, but when it comes to corporate press releases, accuracy and clarity of message are generally secondary in importance. That's because they're more advertising than reporting. If people expected objectivity and accuracy from corporate press releases, they'd look to car manufacturers for useful reviews on their models, energy companies for updates on the latest developments in solar panel tech, etc.
Consider the edits in the context of other publications you've submitted. That will probably tell you if the editor changed the wording out of incompetence/sloppiness or because they wanted to communicate another idea - no matter how inaccurate. For example, Acme co. may want to re-emphasize their presence in the area. Since a company is not expected to adhere to principles of journalistic integrity, they might have decided the best way to grab potential dealers' attention is to give the impression they're "breaking into" the region.
In other words, consider the chances that the editor changed the wording intentionally rather than carelessly, and raise/don't raise the issue depending on your conclusion.
Acme Co expands sales program IN western United States
it would be fine. Butto
makes it sound like we don't currently have anything out there.