If it is noted that a bank has charged a higher late charge than disclosed in the TIL disclosure, do they need to reimburse the difference between what was disclosed and what was charged? I've only found where inaccurate disclosure for finance charge and APR can result in a reimbursable violation. Didn't know if late charge errors were also reimbursable violations.

Assuming the late charge is spelled out in your note and disclosed consistently in your TIL, it's a breach of contract to charge more. Breach of contract probably creates more exposure than the TIL violation. Discuss this problem with bank counsel and prepare to identify all affected customers and refund the overcharges.