Douglas and Joan Wolff know health care costs are skyrocketing, but they found a $15,543 bill for emergency room treatment of Wolff's minor scrapes a little hard to swallow. Speaking of swallowing, Wolff was charged more than $3,000 apiece for the five Tylenol capsules he was given. Mrs. Wolff said Thursday that reading the computerized bill almost sent them both back to the emergency room. ``At first we were shocked. We couldn't believe it,'' she said. ``Then we just had to laugh. We knew it had to be a mistake because all he did was get cleaned up over there.'' St. Mary-Corwin Hospital administrators acknowledged the computer error and assured the Wolffs an amended version of the bill would arrive soon. The bill was not without a touch of heart. The hospital offered the couple a 10 percent discount if the bill was paid within 20 days. The discount of $1,554 would bring the total due down to a mere $13,989.