you are concatenating alot of cells together
=IF(UNIT!E459="WPER",UNIT!I459,"")&IF(UNIT!E459="WINS",UNIT!I459,"")&IF(UNIT!E459="OPS0",UNIT!I459,"")&IF(UNIT!E459="WADJ",UNIT!I459,"")&IF(UNIT!E459="CPLN",UNIT!I459,"")

And they are all using Unit!I459

so that becomes a text rather than a number

so you could add
=VALUE( )
to the formula

=VALUE(IF(UNIT!E459="WPER",UNIT!I459,"")&IF(UNIT!E459="WINS",UNIT!I459,"")&IF(UNIT!E459="OPS0",UNIT!I459,"")&IF(UNIT!E459="WADJ",UNIT!I459,"")&IF(UNIT!E459="CPLN",UNIT!I459,""))
to change the text back to a NUMBER

OR

=IF(OR(UNIT!E459="WPER",UNIT!E459="WINS", UNIT!E459="OPS0", UNIT!E459="WADJ", UNIT!E459="CPLN"), UNIT!I459, "")

And probably simplify with using an Array
OR(UNIT!E459= {"WPER","WINS","OPS0","WADJ",CPLN"}) - but cannot remember the exact syntax - so i will look up or another member will help