IF and ADD formula

welcome to the forum, Neil. a few things to note just for learning's sake
1. if job code is only 27 or 28, and not in decimals, then use OR instead
=-IF(OR($B$57=27,$B$57=28),$E$57)+-IF(OR($B$58=27,$B$58=28),$E$58)+-IF(OR($B$59=27,$B$59=28),$E$59)

2. +- is equivalent to just minus
=-IF(OR($B$57=27,$B$57=28),$E$57)-IF(OR($B$58=27,$B$58=28),$E$58)-IF(OR($B$59=27,$B$59=28),$E$59)

3. and it looks like you can use something shorter:
=-SUMIFS(E57:E59,B57:B59,">=27",B57:B59,"<=28")
or:
=-SUM(SUMIFS(E57:E59,B57:B59,{"27","28"}))

4. to ensure the REF error doesnt happen, you could protect the sheet or use:
=-SUM(SUMIFS(E57:E59,INDIRECT("B57:B59"),{"27","28"}))

do the same for E57:E59 if you need to

=-if(or(index($b:$b,57)={27,28}),$e$57)-if(or(index($b:$b,58)={27,28}),$e$58)-if(or(index($b:$b,59)={27,28}),$e$59)