Here are some alternate rules I've been working on for warp navigation.

Determining Duration of Passage: GM Calculates

Warp Space: Roll 1d10 per square traveled, including the origin square. Keep them on the results on the table or record each number separately.
Real Space: Use 12 days as an average per day in the warp.

Locate Astronomican: +10 Navigation (Warp) Test
Modifiers: ±10 x Degrees to all future tests Navigation (Warp) Tests*
Success: The Navigator removes one rolled die result per degree of success plus an additional die (minimum of the lowest die result)
Failure: The Navigator rolls one die per degree of failure plus an additional die, and adds it to the duration total for warp travel.

Charting the Course: +10 Navigation (Warp) Test*, GM Rolls
Success: +20 to Encounters of the Warp table

Steering the Vessel: Navigation (Warp) Test*
Modifiers: Turbulent -10, Open Warp +20, Established Route +30
Failure: You are throw off course if you rolled a 9 on either die.
Encounters of the Warp: Roll once for each die used toward the duration.

Leaving the Warp: -20 Navigation (Warp) Test*
Failure: Complication