One of my kids teams has a parent that occasionally wears what I thought was an AP RO offshore chrono. He wears a couple watches. Today I had a chance to have a look at it a little closer. It is large and tall (similar to AP) brushed steel with an octagonal bezel that looks like it's integrated into the case. Where the AP has a curved octagon, this was more of a square cut octagon. No hex nuts. Plain strap, no fancy connectors. Black chrono pushers +/- black crown. White date at 3 with no magnifying bubble. It also lacks the bold numerals AP is known for. Tone on tone 6,9,12 chrono dials. Dark blue or black dial.
It looks somewhat like this.

The other thing of note was that the manufacturer seemed to be immediately left of the date in two long thin lines of text, about the same height as the date window It's not an AP or a GP.
Of course I should have just complimented him on it, and I would probably have the answer, but what fun would that be? I even had an interesting watch on myself. It could be months before I see him again and he might be wearing another watch. :(
It likely is a decent watch as he has a couple extremely expensive cars and his wife, who is usually there, has 6-10 carats of diamonds on at any given time and a Rolex masterpiece.