FBR-Inconsistent Dates

I am applying for Foreign Birth's Registration through my grandmother. I have all of the required documentation, but her date of birth and name spelling is inconsistent (on her birth registration her surname is spelled phonetically). On her birth registration, she is recorded as having been born in 1888 while her marriage license reports 1893 and her death certificate reports 1892. The month and day are consistent. Furthermore, her mother's name is not recorded on her death certificate since her husband reported it and had no knowledge of her. Has anyone else been in a similar situation? Am I likely to run into difficulties? Thank-you in advance.

I would definitely get that checked out with the nearest Irish embassy/consulate. The problem is there are too many dates here and there + surname inconsistencies...although it was late 18 early 19th century, so they probably look in to this differently.