This may be dumb, but should I go by the line on the apI test tube? I'm trying to conserve testing fluid as was recommend so I got medicine syringe to be exact. Anyway, my point in all this is my line for my apI test tubes are NOT at 5ml according to a medicine syringe. They are all less than 5. Like 4.6ml and 4.8 ml. Won't ths effect my tests? I'm taken back to chemistry class and titrations where every drop matters.