Facebook Audience Network Filled vs. Impressions

I’m trying out Facebook Audience Network in one of my apps and it seems the filled vs. impressions are way off.

Check out this screenshot:

Screen Shot 2015-07-07 at 1.09.34 PM.png

I understand that not all ads filled will be shown to the user, but coming from Admob it was more like 80% of the ads filled were shown vs. what seems like < 50% for Facebook.

Anyone have any experience with this or explanation?

What is the difference between Filled and Impressions?

Filled is suppose to be the number of requests that had an ad inventory to fill.

Impression is suppose to be the number of filled ads actually shown to the user.

You can see a similar version of this in Admob, if you check the number of requests vs. impressions there, you’ll see that (impressions / requests != fill rate).

Better than the fill rate I am getting…

Screen Shot 2015-07-07 at 6.52.49 PM.png

Does Facebook allow launch and exit ads? What ecpm are you obtaining?

These are my RPM’s over the last several days.

Screen Shot 2015-07-08 at 2.20.42 PM.jpg

Interesting RPM. Do you know if they allow interstitials on launch or exit?