Trending @Infosys; Recently got hiked and promotion

I got hike letter in Feb of 8%. Suppose my salary is 100000 per month, it was now 108000. Yesterday I got the compensation revision letter related to my promotion and it states that my current salary was still 100000 and now it will be 120000. Where is the figure 108000? Shouldn't I be getting promotion compensation above this. Only thing I see is both of the compensation letters are effective from 1st Jan. Is it the case that I haven't got any hike? Please clarify if someone has idea about this.