announcement - just out, page-9

I gotta stop reading CTP announcements, the more I read them, the more I get confused

Ann made on spudding Suprise:

Primary target: Oil in the Pacoota & Stairway Sandstone Formation
Primary target size: 50 million bbls oil in place
Location: Longitude 23 degrees, 42 minutes 50.758 seconds South and Latitude 129 degrees 59 minutes 36.091 seconds East
Target chance of success: 29% (supported by live oil in Johnstone-1)
Formation depth main Pacoota Sandstone Target : 2,600 meters
Equity Interest: Frontier Oil & Gas Pty Ltd (a Central wholly owned subsidiary) (90% and Operator), Trident Energy Ltd (10%)

Recent Suprise update:

Primary target: Oil in the Pacoota & Stairway Sandstone Formation
Primary target size: 50 million bbls oil in place
Location: Longitude 23 degrees, 42 minutes 50.758 seconds South and Latitude 129 degrees 59 minutes 36.091 seconds East
Target chance of success: 40% (supported by live oil in Johnstone-1)
Formation depth: 1,500 meters
Equity Interest: Frontier Oil & Gas Pty Ltd (a Central wholly owned subsidiary) (90% and Operator), Trident Energy Ltd (10%)

Two key factors I see have changed between the two announcements

1) chance of success increased from 29% to 40%
2) The formation depth of the Pacoota & Stairway gone from 2600 metres to 1500 meters.

We are talking about the same formation in both ann yet all of a sudden the formation depth changes to 1500 meters?

Anyone got any idea? :-)