Problem with Proficiency scale (PD) in ESS

Whenever we create qualification update through PA30 or ESS, the system will allow us to save the record without selecting any proficiency scale, i.e., blank proficiency scale "0".

Can we make that field mandatory, so that users have to select something out of proficiency scale?

My client doesnt want the system to allow users to save their record with no proficiency value. please advise