The dipstick on Subaru's is a bit of a funny one, The top hole will show the oil level when cold, the top notch shows the oil level when hot.

To get a good reading, warm the car up, switch off and remove and wipe the dipstick. Leave the car for 5minutes or so with the dipstick out (allows oil to drain from the tube) Then check your levels.

Only read the front side, should have an 'L' and 'F' or 'H' on it, if it doesn't or you can't see anything, normally one side will have a neat line level on and the other will appear to be a bit smudged. (insert dipstick with picture facing forwards so you can read it)

You may find that this provides you with a reading similar on both sides it should certainly help you get a proper reading in any way....