I am quite sure that this is not a Green OakBlue not based on guess work or what I think , but with reference to some sample that I am in the process of compiling to establish the underwing key IDs for this species.
Pending more field data collection and consolidation I will post these keys ID features and review some shots I have posted on this species.
Other than it does not match those key IDs there are a few other difference on the specimen you have shot.
As to what it is I wun even venture a guess without knowing how the upper wings looks like.
A picture is word a thousand words....took the liberty of invereting and mirroring your shot for ease of comparison.
Sunny
~~When the Going Gets Tough, the Tough Get Going~~