Its a Chemistry A2 level exam..... UMS always brings the mark up (for high marks e.g 80% goes to 85%) However I heard it can bring low marks down be the same proportion e.g 30% goes to 25% not 35%
No full raw marks always gets scaled to full UMS, but say the exam is out of 75 raw marks and is really easy, 75/75 would get you 100 UMS but 74/75 could get you something stupid like 93 UMS.