why is the storyline of fma and fmab completely different?

ou see FMAB is following the 日本漫画 so 你 get 更多 details on people and the alchmey abilties it's self if 你 notice in the 2003 version Hughes was killed 由 lust but in FMAB killed 由 Envy who turned into his wife , FMAB and FMA have the same storey line but FMAB witch follows the 日本漫画 add's A LOT of bigger details and has the better plot and is 更多 果酱 packed with information