(e) If subsection (d) applies and the customer proves that the bank
failed to exercise ordinary care in paying the item and that the failure
substantially contributed to loss, the loss is allocated between the
customer precluded and the bank asserting the preclusion according to the
extent to which the failure of the customer to comply with subsection (c)
and the failure of the bank to exercise ordinary care contributed
to the loss. If the customer proves that the bank did not pay the item in
good faith, the preclusion under subsection (d) does not apply.
(f) Without regard to care or lack of care of either the customer or the
bank, a customer who does not within one year after the statement
or items are made available to the customer (subsection (a)) discover and
report the customer's unauthorized signature on or any alteration on
the item is precluded
from asserting against the bank the unauthorized signature or alteration.
If there is a preclusion under this subsection, the payor bank may not
recover for breach of warranty under Section 4-208 with respect to the
unauthorized signature or alteration to which the preclusion applies.
(Source: P.A. 87-582; 87-1135.)