This is how the formula looks in excel...  (I get a syntax error when trying to use formula function in Zoho CRM)

=IF(${Affordability.App 1 Basic Employment Income} -${Affordability.Student Loan - App 1}*12-${Affordability.Pension or Childcare App 1}*12+0.5*${Affordability.Overtime, Bonuses, Commission - App 1}<10600,(${AFFORDABILITY.APP 1 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 1}*12-${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 1}*12+0.5*${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 1}),IF(${AFFORDABILITY.APP 1 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 1}*12-${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 1}*12<42385,((${AFFORDABILITY.APP 1 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 1}*12-${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 1}*12+(0.5*${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 1})-10600)*(1-20%)+10600-(12%*(${AFFORDABILITY.APP 1 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 1}*12-${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 1}*12+(0.5*${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 1})-7750))),(((${AFFORDABILITY.APP 1 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 1}*12-${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 1}*12+(0.5*${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 1})-42385)*(1-40%))+((42385-10600)*(1-20%))+10600-(12%*(42385-7750))-(2%*(${AFFORDABILITY.APP 1 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 1}*12-${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 1}*12+(0.5*${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 1})-42385)))))+IF(${AFFORDABILITY.APP 2 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 2}*12-${AFFORDABILITY.PENSION OR CHILDCARE APP 2}*12+0.5*${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 2}<10600,(${AFFORDABILITY.APP 2 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 2}*12-${AFFORDABILITY.PENSION OR CHILDCARE APP 2}*12+0.5*${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 2}),IF(${AFFORDABILITY.APP 2 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 2}*12-${AFFORDABILITY.PENSION OR CHILDCARE APP 2}*12<42385,((${AFFORDABILITY.APP 2 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 2}*12-${AFFORDABILITY.PENSION OR CHILDCARE APP 2}*12+(0.5*${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 2})-10600)*(1-20%)+10600-(12%*(${AFFORDABILITY.APP 2 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 2}*12-${AFFORDABILITY.PENSION OR CHILDCARE APP 2}*12+(0.5*${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 2})-7750))),(((${AFFORDABILITY.APP 2 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 2}*12-${AFFORDABILITY.PENSION OR CHILDCARE APP 2}*12+(0.5*${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 2})-42385)*(1-40%))+((42385-10600)*(1-20%))+10600-(12%*(42385-7750))-(2%*(${AFFORDABILITY.APP 2 BASIC EMPLOYMENT INCOME}-${AFFORDABILITY.STUDENT LOAN - APP 2}*12-${AFFORDABILITY.PENSION OR CHILDCARE APP 2}*12+(0.5*${AFFORDABILITY.OVERTIME, BONUSES, COMMISSION - APP 2})-42385)))))