Something is way off. Go back to the main page and click the settings gear in the upper right corner and make sure your gallons is right. *edit. I reverse engineered it. Your pool is 154,000 gallons in your settings.
Fix that, then click on the FC tab for the FC dose. Slam for 60 CYA is 24 FC. Enter your current FC, your target (24) and the type of bleach you're using.
And don't feel stupid about botching the test. You dodged a HUGE bullet there. I'd take the goof and a much easier slam, any day of the week.