I booked 2 seats IAH-FRA at T-4 with the cabin being at F5.
Just some additional info... lots of phantom space out there. Website not matching with what the agent could see and vice versa.
However, in the end, UA.com and agent were correct and ANA/KVS were actually incorrect with availability. ANA/KVS showed none, but UA showed 2 seats. I figured it was phantom but called the GS agent to make sure. She was able to book it and I have confirmed seats on LH.com.