swap columns and replace

hi, any problem manipulating (swap coloumn n replace)
example :

File sebelum.txt

1A6Y173BPHE-75.1167.5
1A6Y174BGLY58.7155.7
1A6Y175BARG-18.1142.6
1A6Y176BILE-72.6136.1
1A6Y177BPRO-68.1-136.2
1A6Y178BLYS-162.6360.0

sould be :

File sesudah.txt

1A6YB173PHE-75.1167.5
1A6YB174GLY58.7155.7
1A6YB175ARG-18.1142.6
1A6YB176ILE-72.6136.1
1A6YB177PRO-68.1-136.2
1A6YB178LYS-162.6360.0

you can do it with this script

cat sebelum.txt awk 'BEGIN { FS=""; OFS="" } {$a=$2 $2=$3; $3=$a; print $0 } ' >> sesudah.txt


Note :

FS = Field Sparator
OFS = Output Field Sparator