[Rules] 4th Ed, OBA vs Assault in Ent hex

[richvalle]

I have a single unit and leader in an Ent being assaulted by 3 units of US Inf. The Germans bravely called down OBA onto their own position. 

The way I figured the attack column was: base 16 +1 for 3 units vs the US and base 16 -1 FF, -2 Ent for the Germans.

However, the table says units in a hex with an Ent get the -2. The US units ARE in a hex with an Ent... they way I picture it though is that they are OUTSIDE the Ent even though in the same hex. Since they are assaulting though they could be considered close enough to it to get the bonus?