firstly, it's not good to increase witness from this way.
secondly, it's a danger action to vote like this, when you or BEOS get more vote power, BEOS could take over the chain by add many self account as active witness.
lastly, you have a misunderstanding about the vote mechanism, when there are only 21 active witness, you can't add even 1 witness when you have already vote for more than 21 witness.
on the other hand, you can't reduce even 1 witness when you have already vote for less than 21 witness.
so vote for the one you support, not a random junk account please.