Question

When running Facebook ads using Flexible or Create Ad formats, are they primarily intended for testing purposes only? Once I find a winning creative, is it best to publish that as a post on my Facebook Page and then use “Use Existing Post” for scaling?

I’ve heard that Flexible/Create Ads don’t have stable Post IDs, which might negatively affect long-term performance. On the other hand, using “Use Existing Post” ensures one consistent Post ID, allowing AI to learn better and stack engagement (likes, comments, shares) efficiently.

Is this understanding correct — that “Use Existing Post” ads with a stable Post ID perform better in the long term compared to flexible or create ads?Once I find a winning creative, is it best to publish that as a post on my Facebook Page and then use “Use Existing Post” for scaling?

I’ve heard that Flexible/Create Ads don’t have stable Post IDs, which might negatively affect long-term performance. On the other hand, using “Use Existing Post” ensures one consistent Post ID, allowing AI to learn better and stack engagement (likes, comments, shares) efficiently.

Is this understanding correct — that “Use Existing Post” ads with a stable Post ID perform better in the long term compared to flexible or create ads?

Answer 1

You've hit on a very experienced advertiser's understanding of Meta's ad platform! Your assessment is largely correct, especially regarding the benefits of using an "Existing Post" for scaling.

Let's break it down:

Flexible/Create Ad Formats for Testing

• Intended for Testing (Often): Yes, "Create Ad" (which is essentially a dynamic ad where Meta stitches together various assets you provide) or "Flexible Ad Format" (a newer iteration for multi-asset creative automation) are excellent for initial testing and discovery.

  • They allow Meta's AI to automatically combine different headlines, descriptions, images, and videos to find the best-performing combinations for various placements and audiences. This is efficient for identifying winners.

  • They are great for providing a diverse set of assets to prevent creative fatigue within a single ad set from the get-go.

• Unstable Post IDs (The Core Issue): Your understanding here is accurate. When you use "Create Ad" or "Flexible Ad Format," Meta often generates a unique, dark post ID for each specific combination of assets that it serves. This means:

  • Each unique combination effectively starts with zero social proof (likes, comments, shares).

  • Engagement is fragmented across many different, often invisible, post IDs.

  • The "social stacking" effect (where accumulated engagement makes an ad appear more credible and trustworthy, often leading to better performance) doesn't happen as effectively.

"Use Existing Post" for Scaling

• Best for Scaling a Winning Creative: This is absolutely the best practice once you've identified a winning creative (whether from a "Create Ad" test, an organic post, or even another campaign).

  • Consistent Post ID: When you "Use Existing Post," you select a specific, single post ID. This means all impressions, clicks, and engagement (likes, comments, shares) across all ad sets and campaigns using that specific post ID accumulate on that one post.

  • AI Learning & Social Stacking:

    • Better AI Learning: With a stable Post ID, the Meta algorithm gets a clear, consistent signal about what resonates. All the engagement data funnels into one entity, allowing the AI to learn more effectively from a single source.

    • Efficient Social Stacking: As more people like, comment on, and share that specific ad, it builds social proof. This makes the ad appear more popular and trustworthy to new viewers, often leading to better CTRs and engagement, which in turn can lead to lower CPMs and better ROAS in the long run.