Thanks, I see from their website:
This option uses the wp_is_mobile() function included in WordPress (Codex). If you are unsatisfied with its functionality, have a look at the function in the WordPress core.
I am already using that function manually to show/hide ads per device, so that would not help me. But I see they also say:
This setting does not work properly on cached websites if you don’t use the cache-busting feature in Advanced Ads Pro.
So I will check that out. Are you affiliated with the plugin?