Trending @Infosys; Salary revision for TA promotion

Hi all, I have a confusing between the Yearly hike letter and TA promotion letter. Both of them quoted with effective from Jan 1st but Promotion letter stated with previous salary with unrevised salary before yearly hike. Also why there's a difference is Promotion hike as some of them got 6.8 for TA from 4.2 (>70%)