So long as you have run it for a very short period before you check it you should be fine. The two markers can be thought of as the upper and lower marks on a normal dipstick to anywhere, so anywhere in between covering the bottom on und under the top one should be fine. Dont let it run for too long as you will get a froth of bubbles on the top which makes judging the level difficult. ITs just air from the scavenger pump and they come out eventually!