Concerning Kathavattu and 84000 dhamma

Dear all!
I got a problem with the origin of the number 84000 Dhammakkhandhas.
It is said in Samantapaasaadikaa, in paragraph 16.
"Tadetam sabbampi Buddhavacanam rasavasena ekavidham
dhammavinayavasena duvidham pathamamajjhimpacchimavasena tividham
tathaa pi.takavasena nikaayavasena pa~ncavidham angavasena navavidham
dhammakkhandhavasena caturaasiitisahassavidhanti veditabbam".

In here, caturaasiitisahassavidham, gives a problem of accounting, I
understood it to be 84000 Dhammakkhandhas, and how to count them, I do
understand, but what I do not understand is - is Katthavattu of
Mahamoggaliputta Tissa included in this list or does not? While the
third Council took place, this text was not even in the air, only
after that it was included the canon on every elders agreement, isn't
it?
So, since when is it counted as 84000, and should it include this text?
Thank you very much to every one who can give the answer.