How to get overall A* in edexcel maths

Hi
You are assuming they will hit 90/90 in C3/4

98/99/100 UMS is often hit by students sitting C1 second time around (when they have C3/4 under their belt) after they score in the 80s first time round.
The additional 10 UMS can really take their pressure off either the 2nd applied module or Core 3 and 4 if they do not hit the A star mark and need to ensure they get an A
From experience, many with 262 UMS after As will not go on to hit 90/90 and therefore not get an A star. Many will though but it is not assured and a safety net is always good.
You can aim for one but having 10 easier UMS from C1 can ensure an A if you fall short to ensure an A.
480 UMS for an A so it can be worth banking additional marks if you have dropped 38 in AS.

Hi
You are assuming they will hit 90/90 in C3/4

98/99/100 UMS is often hit by students sitting C1 second time around (when they have C3/4 under their belt) after they score in the 80s first time round.
The additional 10 UMS can really take their pressure off either the 2nd applied module or Core 3 and 4 if they do not hit the A star mark and need to ensure they get an A
From experience, many with 262 UMS after As will not go on to hit 90/90 and therefore not get an A star. Many will though but it is not assured and a safety net is always good.
You can aim for one but having 10 easier UMS from C1 can ensure an A if you fall short to ensure an A.
480 UMS for an A so it can be worth banking additional marks if you have dropped 38 in AS.

If you're a true A* candidate you won't be worried about scraping the 480 - especially if a 90 average is achievable at C3/4. I got 85 in C1 and didn't bother retaking, ended up with 100 in both C3 and C4.

If OP spends enough time on C3/C4 then 180UMS is easily achievable. How well you do really is proportional to how much time you spend on it, if someone aims for 180UMS but misses it I doubt it would be more than just by a bit so retaking something to gain 10UMS is pointless.