So the image is from the actual workbook.
The formulas are
Y14: =ADDRESS(XMATCH(ALL!$AG$5559+0.5,ALL!$AG$1:$AG$5558,1,-1)*1,11)
Y16: =ADDRESS(XMATCH(ALL!$AF$5559+0.5,ALL!$AF$1:$AF$5558,1,-1)*1,11)
Y19: =ADDRESS(XMATCH(ALL!$AG$5559-0.5,ALL!$AG$1:$AG$5558,-1,-1)*1,11)
Y21: =ADDRESS(XMATCH(ALL!$AF$5559-0.5,ALL!$AF$1:$AF$5558,-1,-1)*1,11)
These are all producing a result (shown in the image).
Y19 & Y21 are producing the correct result but I think this is because the formula has found a 9 (1 less than 10) and that happens to be the next lowest score.
However Y14 & Y16 are producing an incorrect result as they are looking for 11 (1 more than 10) but are ignoring higher numbers that come before an 11.
So I think I just need to alter the formulas to include greater than > and less than < but I can't find the right position.
This is so close to perfect.