multiple if statement not working but not working (make sense!)

I have a multiple condition if statement that uses two drop downs to derive the resulting value, the issue is that the first time you switch between the drop down values it works, but when you want to switch back it wont. how do i clear it?
the two drop downs are employee type = resourcer, consultant
override = yes, no

when i change employee type (c8) =resourcer and override(03) =yes it works, but when i swap back to employee type (c8) = consultant and then override (o3) = no, it doesn't change back to the correct value. However iwhen i open the file and the first option i choose is employee type =consultant and override = no, it works just fine

this is the rule

=IF(O3="No",
IF(AND(C8="Consultant",C11>=2,C13>=10,C15>=3,OR(C12>=5,C10>=1)),"Target Achieved",
IF(AND(C8="Resourcer",C14>=15,C12>=5),"Target Achieved","Target Not Achieved")),
IF(
IF(AND(C8="Consultant",C11>=2,C13>=10,C15>=3,OR(C12>=5,C10>=1)),"Target Achieved",
IF(AND(C8="Resourcer",C14>=15,C12>=5),"Target Achieved","Target Not Achieved")="Target Achieved")="Target Achieved","Target Achieved","Target Not Achieved"))


basically what i am trying to do is say whether a resourcer or consultant has made their targets, but if a manager wants to override the target result based on the calculation, they can use the override drop down to change the value