Todays shale discovery has a recoverable range of 7.9-23.6 MB.
Pre drill the expected result for both the Lower and Upper Antelope Shale was 7.7MB. At this time the Upper Antelope shale has not been tested but drill thickness indicated the upper zone to be about 50% of the Lower zone.
On this basis is seems the pre drill estimate for this particular zone is at least 50% higher than expected.