I don't know what you are doing but here is the result of my query.

Depart Arrive Flight # and Details
11:20 PM 26 Apr 2008
San Francisco, CA 5:16 AM 27 Apr 2008
Chicago, IL (O'Hare) Flight: 6967
Class: Coach Boeing 767-300
On-Time: N/A Meal: None
Travel Time: 3 h 56 m
6:40 AM 27 Apr 2008

Chicago, IL (O'Hare) 9:29 AM 27 Apr 2008
Charlotte, NC Flight: 5906
Class: Coach Boeing 737-300
On-Time: N/A Meal: None
Travel Time: 1 h 49 m
11:21 AM 27 Apr 2008

Charlotte, NC 1:37 PM 27 Apr 2008
San Jose, Costa Rica Flight: 1773
Class: Coach Boeing 757-200
On-Time: N/A Meal: Buy on Board
Travel Time: 4 h 16 m

Return Arrive Flight # and Details
2:35 PM 28 Apr 2008
San Jose, Costa Rica 8:45 PM 28 Apr 2008
Charlotte, NC Flight: 1774
Class: Coach Boeing 757-200
On-Time: N/A Meal: Buy on Board
Travel Time: 4 h 10 m
10:15 PM 28 Apr 2008

Charlotte, NC 11:55 PM 28 Apr 2008
Philadelphia, PA Flight: 1586
Class: Coach Boeing 757-200
On-Time: 70-80% Meal: None
Travel Time: 1 h 40 m
7:40 AM 29 Apr 2008

Philadelphia, PA 11:00 AM 29 Apr 2008
San Francisco, CA Flight: 657
Class: Coach Airbus A319
On-Time: 70-80% Meal: Buy on Board
Travel Time: 6 h 20 m

Summary (1 Passenger) Base Fare $218.00
Taxes and Fees $80.50
Grand Total Hide Details $298.50

Passenger Type Adult
Fare
SFO to SJO - Fare Basis KH3SA $109.00
SJO to SFO - Fare Basis KH3SA $109.00
Adjusted Base Fare $218.00
Total Fare $218.00
Tax: US International Arrival $15.40
Tax: US International Departure $15.40
Tax: Costa Rica Common Area User Charge $3.30
Fee: US Immigration $7.00
Fee: US Animal & Plant Health Inspection Svc. $5.00
Fee: US Customs User $5.50
September 11 Security Fee $10.00
Fee: US Passenger Facility Charge $16.50
Costa Rica International Security Fee Arrival $1.20
Costa Rica International Security Fee Departure $1.20
Total Per Passenger $298.50
Number of Passengers 1
Total by Passenger Type $298.50