Praise be to Allah.
The Muslim – whether he is an imam or praying behind an imam – should always be keen to pray as the Prophet (blessings and peace of Allah be upon him) used to pray, in accordance with the words of the Prophet (blessings and peace of Allah be upon him): “Pray as you have seen me praying.” Narrated by al-Bukhaari (631). And he should not introduce anything into the prayer, especially that for which there is no basis in the religion of Allah and that was not the practice of the people before.
Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him) said: The best for the imam is to strive to emulate the way in which the Messenger of Allah (blessings and peace of Allah be upon him) used to lead his companions in prayer. In fact this is what is prescribed and is enjoined by the leading scholars… So the imam should usually do what the Prophet (blessings and peace of Allah be upon him) usually did, then if there is an interest to be served by making it longer than that or shorter than that, he may do that, as the Prophet (blessings and peace of Allah be upon him) used to sometimes make the prayer longer or shorter.
End quote from Majmoo‘ al-Fataawa (22/315-318)
From what has been mentioned about the prayer in the mosque referred to, there are several things that are contrary to the Sunnah, including the following:
Programming every prayer to be at a specific time is undoubtedly contrary to the Prophet’s Sunnah; moreover, it is an innovation that was not the practice of the earlier generations and is not known from the imams of guidance and leading Muslim scholars throughout the ages – as far as we know – rather what is known is something other than that.
Making Fajr prayer equal in length to Maghrib and ‘Isha’ prayers is contrary to the Sunnah that has been narrated from the Messenger of Allah (blessings and peace of Allah be upon him).
The usual practice of the Prophet (blessings and peace of Allah be upon him) was to make Fajr prayer lengthy, ‘Isha’ prayer moderate in length and Maghrib prayer brief, as it was narrated by an-Nasaa’i (982) from Sulaymaan ibn Yasaar that Abu Hurayrah said: I have never prayed behind anyone whose prayer more closely resembled that of the Messenger of Allah (blessings and peace of Allah be upon him) than So and so. Sulaymaan said: He used to make the first two rak‘ahs of Zuhr lengthy and make the last two brief, he made ‘Asr brief, he recited the short soorahs of al-Mufassal in Maghrib, he recited the medium soorahs of al-Mufassal in ‘Isha’ and he recited the lengthy soorahs of al-Mufassal in Fajr.
Classed as saheeh by al-Albaani in Saheeh an-Nasaa’i. please see also the answer to question no. 162900
Making the first rak‘ah of ‘Isha’ or any other prayer the same as the length of the second rak‘ah, and defining that in terms of minutes, is also introducing something that is contrary to the Sunnah, because what the Prophet (blessings and peace of Allah be upon him) usually did was to make the first rak‘ah longer than any other. Please see the answer to question no. 171060.
Making the imam persistently perform the prayer in a manner that is contrary to that which is narrated in the Sunnah, and taking him to task if he goes against that is – in addition to going against the Sunnah – is disrespectful towards the one who is leading you in the prayer and obliging him to do something that he is not obliged to do; it is contrary to the status of the act of worship and to what is expected of honouring the one who stands before the worshippers to lead them in prayer, who should be one of the people of the people of the Qur’an or should be the most knowledgeable of the worshippers about the Qur’an. It is turning away from all of that and making it more like purely routine administrative work. So it becomes like a job with rules and regulations that the imam may have to put up with for the sake of what he gets of a salary and a livelihood.
What you should do is advise the administration of the mosque and come to some agreement with them concerning this matter, on the basis of wisdom and kindness, so that the mosque will be paying attention to the Sunnah in the best manner and adhering to it.
With regard to defining the time between the adhaan and iqaamah for each prayer in a way that will best serve the interests of all, it does not seem to us that there is anything wrong with that; in fact most of the mosques do that, setting a time for the iqaamah, so that the people will know the time of the prayer and will not miss it.
For more information on that, please see the answer to question no. 160000
And Allah knows best.