All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
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The scholars of the Hanbali School are of the view that it is an obligation to say, "Subhaana Rabbiyal-A’theem," in Rukoo’ and say, "Subhaana Rabbiyal-A’la," in Sujood; so saying any other kind of mention of Allaah is not sufficient according to them.
Hence, you have to say this specific Thikr (mention of Allaah) lest your prayer be subjected to being void according to the scholars of the Hanbali School. Besides, it is only obligatory to say this Thikr once, and saying it more than once is desirable. So if you say this Thikr once and then say another kind of Thikr, there is no harm in doing so.
In case you wish to say other kinds of Thikr as well as the obligatory Thikr, then it better to say something that is confirmed in the Sunnah, such as saying, "Subbooh-un Quddoos-un Rabb-ul Malaa'ikati war-Rooh;" or, "Subhaanaka Allaahumma Rabbana wa Bihamdika, Al-Laahummaghfir li;" or, "Subhaana Dhil-Malakooti wal-Jabarooti wal-Kibriyaa’i wal ‘Athamah." Also, you should supplicate as much as possible in prostration and say the Athkaar that we have mentioned, which are the Athkaar that were confirmed from the Prophet as there is much goodness in them. However, if you say other kinds of Thikr, such as what you have mentioned in your question, then there is nothing wrong with that on the condition that you say the obligatory Thikr as well as what we have already stated.
Allaah knows best.