When I open a new data section in the submiit data page, all the fields are leaved blank, and I don't now if a precedent update ad occurs. So it may possible i update more and more the same aircraft.
If the mode S code was updated, I don't redo and redo to send useless message that congested your entries.
I have a decoder of mode S code and i receive aircrafts as soon as the airccraft are in visibility of my antenna (at hight altitude sometimes more of two hundred of miles).