The short version
The cost of a change rises roughly tenfold at every stage. Pre-production is where changes are still nearly free.
What is really going on
A script change costs an hour; the same change after animation costs a week.
Style frames resolve subjective disagreement before it is attached to motion nobody wants to discard.
An animatic exposes structural problems that are invisible in stills.
How to handle it
Refuse to start animation without written approval of the boards.
Spend real money on style frames — they are the cheapest insurance in the process.
Cut the animatic with temp sound at final duration before committing to render.
The takeaway
Every hour spent in pre-production buys back several in animation. The ratio is not close.
