Some student combine result for different reasons. This reason can all be traced back to partial failure or mis-enrolment of the subject. The major reason why people combine result is
Mis-enrolment of subject
Change of course
The above three are the main reason why student combine result.
Every school require a minimum of 5 credit load from either waec or NECO exam to admit any student.
If for example, a student have three credit load in waec, then he/she can still gain admission by writing the neco exam and then combining both.
If the student gets all credit load in all five subject, then the student can use NECO to gain admission but if he/she doesn’t like neco because of its limitations in Nigeria, he/she can combine both the NECO result and waec result to gain admission.