Most examiners read a high rod tip as slack, and it is. With 5 feet out it hardly matters; with 50 or 60 feet you have to get the rod way back before the slack comes out, and by then your fly is hitting the water behind you.

What the instructor says

• The exam answer. “There’s slack when you pick it up” is what he wants to hear — and what most examiners read from a high tip.
• 5 feet versus 50–60 ft. Task 1 is 40 feet, short enough to get away with it, but the low tip is a habit for longer line.
• Before every task, lay the line down straight, tip down — the roll cast is the only exception.
• Reset cleanly. If a wiggle mend left a mess, roll cast pickup and lay it down.

Putting it to work

1. Lay the line down straight, rod tip down, before every task except the roll cast.
2. Try a high tip with 60 feet out and watch the fly land behind you.

Source

From the FFI CI walkthrough series by Dayle Mazzarella (Chapter 3 — FFI Casting Instructor Certification Tasks, Fly Fishing Coach International), lesson 2, 00:03:12. See the video library and the task pages for the exam wording; terms follow the FFI Fly Casting Definitions.