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Hi,

Is there anything i can do to improve this formula,

=IF($A3<>"",IF(Jan!$E6<>"",LET(d_patt,IF(Jan!$E6<>"",VLOOKUP(Jan!$E6,SETTINGS!$A$12:$B$27,2,FALSE)&IF(Jan!$B6<>"",Jan!$B6,0)&IF(Jan!$C6<>"",Jan!$C6,0)&IF(Jan!$D6<>"",Jan!$D6,0),""),"ROT"&IF(LEN(Teams!$BHR4)>0,MID(Teams!$BHR4,MOD(NETWORKDAYS.INTL(Teams!$C4,I$2,"0000000")-1,LEN(Teams!$BHR4)/3)*3+1,3),"000")&IF(LEFT(d_patt,3)="OVT",d_patt,"OVT000")&IF(LEFT(d_patt,3)="SSI",d_patt,"SSI000")&IF(LEFT(d_patt,3)="SSO",d_patt,"SSO000")&IF(LEFT(d_patt,3)="SDS",d_patt,"SDS000")&IF(LEFT(d_patt,3)="HOL",d_patt,"HOL000")&IF(LEFT(d_patt,3)="LID",d_patt,"LID000")&IF(LEFT(d_patt,3)="UNP",d_patt,"UNP000")&IF(LEFT(d_patt,3)="FLD",d_patt,"FLD000")&IF(LEFT(d_patt,3)="MAT",d_patt,"MAT000")&IF(LEFT(d_patt,3)="LIS",d_patt,"LIS000")&IF(LEFT(d_patt,3)="CBR",d_patt,"CBR000")&IF(LEFT(d_patt,3)="ABS",d_patt,"ABS000")),"ROT"&IF(LEN(Teams!$BHR4)>0,MID(Teams!$BHR4,MOD(NETWORKDAYS.INTL(Teams!$C4,I$2,"0000000")-1,LEN(Teams!$BHR4)/3)*3+1,3),"000")&"OVT000SSI000SSO000SDS000HOL000LID000UNP000FLD000MAT000LIS000CBR000ABS000"),"")

i currently use this on a sheet 149,200 times so as you can image is affecting performance, i have already reduced this by using the let function, but still feel more could be done, the header is the date of the year, and each row is a colleague, here is an example string used for the rota pattern. this is taken from another sheet, that unless changed remains fairly static, but needs to be easily updateable.
000800800800800800000000080080080080000800800800800000000800080080080000080080080000000800800800800800000000080080080080000800800000000800800800080080000080080080080000

Thanks