Should: 'I63aam (it'aam) preferably be written without or with 'alif according to the 3Uthmaanic rasm, in Al-Balad (90:14:2)?

Question
Assalaamu 3alaikum,
Should: 'I63aam (it'aam إطعام) preferably be written without or with 'alif according to the 3Uthmaanic rasm, in Al-Balad (90:14:2)? For example the Madinah Complex Hafs and Warsh have it spelled differently, what is the cause of that? Are there more such cases?
Answer
Wa alaikum assalaam wa rahmatullahi wa barkaatuh
There are some words which were found to be written different ways in the early mushaahif of the Sahabah and the Khaleefa 'Uthmaan instructed the scribes to send one way to a certain area and the other way to another area according to the way of recitation prevalent  and the way it was found in the mushaf for that way of recitation.
In the case of إطعام it is written with an alif after the letter عين in some copies and without an alif in other copies of the mushaf in surahs Al-Maa'idah, Al-Mujaadalah, and Al-Balad. There other many other examples with other letters. 
There are also some word combinations which are sometimes written together and other times written separately in the mushaf with some cases of differences between copies of the mushaf. 
To see more about this last case please see:
http://www.abouttajweed.com/index.php/tajweed-rules/64-al-maqtoo3-and-al-mawsool/90-words-written-separately-and-together-al-maqtoo3-al-mawsool-1