Unknown extra mark on dipstick, Why? Options

[mankowski]

My stock 1.7 has an extra mark below the low mark on the dipstick. The original full and low marks are where they should be - 30 mm and 23 mm respectively from the end of the stick.

Mine has an additional one, about 17 mm from the end.

Any guesses about what possible purpose would a prior owner have had in making this mark?

I have not seen it on other dipsticks.

Unfortunately, I have been using it as the low mark for determining when oil is needed — until measuring it today — but no more! No telling what damage may have occurred from running too little oil for this long.