Thank you for following up with me.
As a technical matter, yes, if the POA specifies access to bank accounts then you should have proper authority to obtain information and you can make the request.
However, I will tell you that, in my experience, banks can be "resistant" about it. Often, they will insist on their own POA form being executed before the information will be released. That would, obviously, require your uncle's cooperation.
They usually have a couple of reasons. First, the account agreement would specify that the bank's forms are required for any POA or other authority. Second, the bank would want to be released and indemnified for any privacy claims from the principal (your uncle, in this case).
I hope this answers the question.