FWIW, ThrillSeekerVR who helped who provided some unpaid feedback on the development of this headset, also mentions in his video that he personally measured the FOV as higher than the specs list and quotes the CEO of Bigscreen as saying that he plans to "underpromise and overdeliver" on that front: https://youtu.be/mieWJ9vupqw?t=183
Screenshot from above video: https://imgur.com/0JVeyRC