Yeah, you're not actually getting paid 2 extra salaries, it's just your yearly salary divided by 14 instead of 12. The only extra si you pay less tax on those 2 extra salaries so you get more money in your pocket before summer and Christmas.

I guess when the 13 and 14 was added it was essentially a pay increase in some negotiation? And stuck around? However, if the company has more money in some point of the year, it makes sense for them to pay more wage at that time.