Several people ove here in Oz have had issues over the years with oil on the AMS, screwing their air flow data and hence the tune, resulting in bad running.
Good tuners avoid them.
Add to the fact that, well the ain't no free lunch - the "greater airflow", well at least initially, is from having bigger holes in the filter that allow small fines to get through, polluting your engine oil and wearing your bores and bearings.
And when they get dirty, they flow worse than factory paper filters.