I use Interparcel to sell parcels on a regular basis by batches in one time. For every 20 parcels sent they lose 1 and return a standard response of "a sweep has been conducted and the parcel can't be located so it has been declared as lost"! No effort to actually find the cause of the "loss" even though some state the parcel was with the delivery driver but never delivered and then conveniently "lost". This is a catch 22 so you either pay the extra for insurance or you accept you will lose a parcel for every 20 sent essentially meaning you will pay more regardless!