Answer
Wa Alaikum Assalam Wa Rahmatullahi Wa Barakatuh,
Thank you for your question and for contacting Ask About Islam.
Concerning the moon cycle, a lunar month may only be 29 or 30 days so if there is a confusion about sighting the moon then the difference should not be more than one day.
I can see two extremes, one who must see the moon even after few days, which is wrong since if you don’t see it on the 29th of Shaban then simply complete the 30th of Shaban and Ramadan will be the following day; we read in the hadith:
It was narrated that Ribi said:
The Messenger of Allah said: ‘When you see the crescent then fast, and when you see it (at the end of Ramadan), then stop fasting. If it is too cloudy then complete Shaban as thirty days, unless you see the crescent before that. Then fast Ramadan as thirty days, unless you see the new crescent before that.’ (An-Nasai – Sahih)
The other extreme is more political and they announce Ramadan either too early or too late, knowing what the calculation has already been predicted.
So a lunar month cannot be 28 days or 31 days. If it is thirty days then the following month has a high possibility of being 29 days and vice versa.
It is not a problem that you differ one day from Saudi Arabia as long as your entire country is beginning the fast on the same day and performing Eid on the same day as well.
Unity in the same country is what is important. If a group says, they would like to follow Saudi Arabia then there is always another group that will object. but if you all agree on a day based on your own moon citing then there should not be any confusion.
Obviously, if you have decided to follow a country, it is better to follow the one that has the same timing as yours.
I hope this helps answer your question.
Salam and please keep in touch.
Please continue feeding your curiosity, and find more info in the following links:
https://aboutislam.net/science/faith-science/knowing-what-a-lunar-based-calendar-is/
https://aboutislam.net/science/faith-science/towards-a-unified-islamic-calendar/