Spelling of Mohammad vs Muhammad - Pakistan I 130 application

[ilyas]

I am Pakistani American and applied for my sibling’s immigration via I-130. I attached NADRA's issued family registration certificate as a proof of relationship. But USCIS asked me to provide birth certificates. My family back home, get certificates on my request and we provided to USICS. But USICS objected that they were just obtained now and had late registration. They asked some other proof such as education records etc. I am thinking of providing matric certificates of my siblings as that has my father name. But have just noticed that in certificates the spelling of Muhammad is not same for my father. 2 of my siblings has my father name starts with Mohammad and for other two it starts with Muhammad, in their certificates (difference of vowel letters 'U' and 'O'). Please advise me how we can provide an explanation to USCIS that this is same name. This was never an issue in Pakistan and we all know that this is the same name. It will be highly appreciated.