There is big difference between Qira'aat and Ahruf. Qira'aat are ways of reciting the same words of Quran according to the axon of different Arab tribes. Qira'aat keep the meaning same with slight different way of pronouncing the words .
Ahruf (plural of Harf) means different wordings. This claim of Ahruf was condemned by Ahlul Bayt (AS) who clearly said that Quran was sent from One Allah, on One Prophet, through One Angle and on one word not more.
From al-Fudhail Ibn Yasaar said: I told Abi Abdillah (Al-Sadiq A.S.): People say that Quran was revealed on seven Ahruf (words). He said: They are liars, enemies f Allah. Quran was revealed on One Word from The One . (Kitab Al-Kaafi).
We do not believe in more than one Harf of Quran which means one wordings not more. Different wordings means different meanings which is false claim.