Question
What is the ruling behind using the letter Sa'd when there is a little 'seen' on top of it?
Answer
Assalaam alaikum,
There are some Arabic words that originally have a

, but when the letter

is near it, it is pronounced and written by some Arabs tribes as a

. This is reflected in the Qur'an, as it was revealed in the language of the Arabs. There are four words in the Qur'an in which the

is written with a

and read by some of the Qira'aat or in some of the turuq of Hafs with a

and by other turuq or other qira'aat as a

. Sometimes in one tareeq or qira'ah it is allowed to read it either with a

or a

.
These four words are the words in red in the following examples:

In the Medina Printing Complex copy of the Qur'an for Hafs, the words are written with the reading of Hafs 'an 'Aasim by the tareeq Ash-Shaatibiyyah in mind. The first two examples are read with a

, and thesmall letter

is written above the

to show that we read it with a

. In the third example, it is allowed to read with either the

or the

, so the

is written below the

. In the last example, it is read with only a

by Hafs 'an 'Aasim by the tareeq of Ash-Shatibiyyah, so it is written with the

only, with no small

added in the enhancements of the writing.
We cannot use the placement of the

over or under the

as a tool in other musaahif as they may not be following the qira'ah of Hafs or not the tareeq of Ash-Shaatibiyyah.
If you are only reading Hafs 'an 'Aasim by the tareeq of Ash-Shatibiyyah, then you should follow the rules outlined for reading with a

or a

in the four words above irregardless as to the placement of the small

over or under the

in the copy of the Qur'an that you are using.