WARNING: This page is about a different car, the 2008 Subaru Tribeca, 2008 Subaru Outback, and 2008 Subaru Legacy. However, it is still accessible from the selected car via links, so may be relevant.
When the ATF temperature is low, the line pressure control characteristics is set higher than normal so that the clutches and brakes will operate at an earlier stage.
Fig 1: Identifying Graph (Line Pressure Control When ATF Temperature Is Low)