Tax credit limit: deductee's credit capped at full disputed tax despite higher payment requirement in search or late-payment cases. Tax credit available to a deductee is capped at one hundred percent of the disputed tax and cannot exceed the disputed tax amount even where the payer is required to remit an amount exceeding the disputed tax to settle a Section 201 appeal; this applies whether the excess payment arises from a search case or from late payment after the relevant cutoff.