I don't understand what is the different between a 2 for 1 stock split and a 1 for 1 stock split. If you have 100 shares then get a 2 for 1 split you will have 200 shares. If you have 100 shares then get a 1 for 1 split won't you still have 200 shares (100 shares + 100 shares = 200.
I'm guessing you're conflating
bonus share issuance with
stock split. That seems very common to me, from a quick search; there's even some issues of terminology between the US and Europe, I think - it seems some Europeans may use Bonus Shares to mean Stock Split, as opposed to the more common meaning in the US of Stock Dividend.
Sometimes a bonus share issuance is (incorrectly) called a stock split, like in this public announcement from STADA in 2004. It is a 1:1 bonus share issuance (meaning they issue one bonus share to everyone who has one share now), but it is in essence the same thing as a stock split (a 2:1 stock split, namely). They combined the 1:1 from bonus share with the wording 'split', causing the confusion.
Bonus share issuance, also known as a stock dividend, is covered well in this question/answer on this site, or from a search online. It has no obvious effect initially - both involve doubling shares out there and halving the price - but it has a substantially different treatment in terms of accounting, both to the company and to your tax accountant.