if you take a pill with 20 mg of paxil/déroxat/paroxétine, the 20 mg active molécules are mixed in a support component, normally it is good mixed, homogeneously,
this is theorical, only the laboratory knows what he has done;
the psychiatrist i visit 8 months told me, when a pill has in the middle the original possibility of cutting in two parts, there is the half of paxil actives molécules in each part, so 10 mg active paxil molecules, but if we cut a corner of the part which has not been planned to be split, we are not sure of the amount of active molecules we have in this component support;
dixit the psychiatrist(and i think they have studied this in school), we can have 3 mg actives instead 5 mg; this is normal for him, because the pills has been created to be swallowed entire or half splitting, but not scratching a corner

what is the truth?

i think the bottle syringe system is more reliable, or the titration of the pill in water or milk and shaking, and drinking an amount percentage