Fwiw, I don't think the 3 hour rule applies to D1/SkyTeam business class passengers either. So it's fundamentally not an issue. Delta website makes no mention of 3 hour restriction. And anecdotally, I arrived at the SkyClub outside of my 3 hour window (not by a lot) before my flight to CDG and it wasn't an issue. I actually did see on the staff's scanner that a 3 hour thing popped up, but she dismissed it.