How likely is it that my grade will go up (A to A*)

I am currently in the process of submitting remarks in the following: further maths, chemistry, physics. My question is how likely is it that my grade will go up.

Chemistry
Currently at 98/120
Need 108/120 to go up to an A*
10ums is roughly 5 marks

Physics
Currently at 98/120
Need 103/120 to go up to an A*
5ums is roughly 2-3 marks

Further Mathematics
Currently at 77/100
Need 87/100
10 ums is roughly 5marks. Also felt I got all marks, so the relative low score is surprising.

All comments are appreciated

5 marks is a lot for examiners to miss, especially for your subjects in which pretty much every answer is right or wrong so they don't have to use their discretion.

Chemistry - unlikely as explained above
Physics - possible, you could pick up 2-3 marks in one question
Further maths - normally I'd say unlikely but if you think you did really well then perhaps the examiner missed something big

That having been said, you never know what could happen so it's always worth a shot if it matters to you.