EXACT Functionality with nn-sequential coloumns

[vsbhogar]

My code for calculating alphabetic grade is below,it is working properly for sequential coloumns

How to change this code ,when non-sequential columns are considered ,means how EXACT(R5:V5) will be change if R5,T5,V5 are only considered for EXACT function

=IFERROR(IF(SUMPRODUCT(--EXACT($R5:$V5,"a"))>0,"a",IF(((COUNTIF(R5:V5,"A")*3)+(COUNTIF(R5:V5,"B")*2)+(COUNTIF(R5:V5,"C")*1))/COUNTA(R5:V5)>=2.1,"A",IF(((COUNTIF(R5:V5,"A")*3)+(COUNTIF(R5:V5,"B")*2)+(COUNTIF(R5:V5,"C")*1))/COUNTA(R5:V5)>=1.1,"B",IF(((COUNTIF(R5:V5,"A")*3)+(COUNTIF(R5:V5,"B")*2)+(COUNTIF(R5:V5,"C")*1))/COUNTA(R5:V5)>=0.1,"C","")))),"")

[martindwilson]

why are you using that ridiculously long formula when i gave you a far shorter version ?
AS LONG AS all CELLS ALL HAVE SOMETHING IN THEM
=LOOKUP(SUMPRODUCT((ROUND(1/((CODE(R5:X5)-64)/3),0))*(MOD(COLUMN(R5:X5),2)=0))/4,{0,0.1,1.1,2.1},{"no grade","C","B","A"})
for example will only consider cells r5,t5,v5,x5