After Update statement

i have a problem. I want to achieve this

total2=gross_Salary+perquisites+profits
total3=house_rent+transport_allowance+others

i used AfterUpdate() function on form to do the calculation and to save the results in the table.

Private Sub grossSalary_AfterUpdate()
Me.total2 = Me.grossSalary + Me.perquistes + Me.profits
End Sub

Private Sub perquistes_AfterUpdate()
Call grossSalary_AfterUpdate
End Sub

everything is working fine till there. Now in the next fields i have to do calculation on these calculated results and save the results in table.

I want to achieve this:
Gross_taxableSalary=total2-total3

I tried to use the AfterUpdate function again, but this time its not working.
Private Sub total2_AfterUpdate()
Me.gross_taxableSalary = Me.total2 - Me.total3
End Sub

Private Sub total3_AfterUpdate()
call total2_AfterUpdate()
End Sub

Please help me. its very urgent.