Praise be to Allah.
The basic principle with regard to supplication (du‘aa’) is that it is permissible so long as it does not include anything that is not allowed, such as praying to commit sin.
Praying for al-waseelah [the highest station in Paradise] for the Prophet (blessings and peace of Allah be upon him), such as saying, “Allaahummah aati Muhammadan al-waseelata wa’l-fadeelah, wab’athhu maqaaman mahmoodan alladhi wa’adtahu (O Allah, grant Muhammad the highest station in Paradise and distinction, and resurrect him to the station of praise and honour that You have promised).” This supplication is good, with a beautiful meaning, and is proven in the Sunnah, so there is nothing wrong with saying it at any time of offering supplication, even if it is not the time that is mentioned in the Sunnah. It does not seem to us that there is anything wrong with that.
But the Muslim should be keen at every time or place of offering supplication to begin with the soundly-narrated supplications that are specific to that time or place, then he may offer whatever prescribed supplications he wishes after that. That includes praying for al-waseelah (the highest station in Paradise) and the maqaam mahmoud (station of praise and honour) for the Prophet (blessings and peace of Allah be upon him).
Moreover, it should be noted that this du‘aa’ should not be taken as something to be recited at any time, without paying attention to the specific time it is to be said, which is after the adhaan, and without making sure to say it regularly at the time for which it is prescribed in the Sunnah.
The Muslim should stick to the order of phrases and sentences mentioned in the du‘aa’s that are narrated in the Sunnah, because by doing so he will be perfectly following the example of the Prophet (blessings and peace of Allah be upon him.
Allah, may He be exalted, says (interpretation of the meaning):
“There has certainly been for you in the Messenger of Allah an excellent pattern for anyone whose hope is in Allah and the Last Day and [who] remembers Allah often”
If the one who is offering supplication does not understand Arabic, and he changes the order of phrases in the du‘aa’, that may lead to him changing the meaning. It says in Fataawa al-Lajnah ad-Daa’imah li’l-Buhooth al-‘Ilmiyyah wa’l-Iftaa’:
The scope of supplications is broad, so let the individual pray to his Lord for what he needs, so long as there is no sin involved in that.
But with regard to the du‘aa’s and dhikrs that are narrated from the Prophet (blessings and peace of Allah be upon him), the basic principle is that they are to be recited as they are, in terms of the wording and the number of times that the du‘aa’ is to be repeated. So the Muslim should pay attention to that and adhere to it, and not add to the number specified, or to the wording, or take anything away from that, or change any of the wording.
Al-Lajnah ad-Daa’imah li’l-Buhooth al-‘Ilmiyyah wa’l-Iftaa’
‘Abdullah ibn Qa‘ood, ‘Abd ar-Razzaaq ‘Afeefi, ‘Abd al-‘Azeez ibn ‘Abdullah ibn Baaz.
End quote from Fataawa al-Lajnah ad-Daa’imah (24/203-204).
And Allah knows best.