Syncsort Join two files

Question

I am trying to join two files based on a key and add a new column in the result based on a condition , but I am not able to figure out why my condition in command is not working. Please help me understand correct way of doing this.

a.txt

3~Y
4~0
1~Y
2~N

b.txt

4~44~444
3~33~333
2~22~222
1~11~111

Syncsort Command

/INFILE a.txt  ALIAS DOC '~' 3000
/JOINKEYS BA1
/FIELD DOC_Rest1 2:1 - 2:
/INFILE b.txt ALIAS FINACT '~' 3000
/JOINKEYS BA2
/FIELD FINACT_DID 2:1 - 2:
/FIELD FINACT_PILOT 3:1 - 3:
/FIELDS BA1 1:1 - 1:, BA2 1:1 - 1:
/COND CHKINCCALS (DOC_Rest1 = 'Y')
/DERIVEDFIELD  endofrecord '\n'
/DERIVEDFIELD TYPECAL
        If CHKINCCALS then FINACT_DID
        Else FINACT_PILOT
/OUTFILE c.txt OVERWRITE  /REFORMAT  LEFTSIDE:BA1,LEFTSIDE:DOC_Rest1, TYPECAL, endofrecord
/END

Expected result

1~Y~11~
2~N~222~
3~Y~33~
4~0~222~

Actual result

1~Y~Y~
2~N~~
3~Y~Y~
4~0~~

Answer 1

After some guess work, I was able to figure out the correct way. I am still not sure how it works though.

/INFILE a.txt  ALIAS DOC '~' 3000
/JOINKEYS BA1
/FIELD DOC_Rest1 2:1 - 2:
/INFILE b.txt ALIAS FINACT '~' 3000
/JOINKEYS BA2
/FIELD FINACT_DID 2:1 - 2:
/FIELD FINACT_PILOT 3:1 - 3:
/FIELDS BA1 1:1 - 1:, BA2 1:1 - 1:
/COND CHKINCCALS (DOC_Rest1 = 'Y')
/DERIVEDFIELD  endofrecord '\n'
/DERIVEDFIELD TYPECAL
        If CHKINCCALS then RIGHTSIDE:FINACT_DID
        Else RIGHTSIDE:FINACT_PILOT
/OUTFILE c.txt OVERWRITE  /REFORMAT  LEFTSIDE:BA1,LEFTSIDE:DOC_Rest1, TYPECAL, endofrecord
/END