BSP HAP_DOCUMENT validate appraisal info

Hello,

I´ve copied HAP_DOCUMENT BSP aplication to a Z one,

When I change the appraisal status from "In preparation" to "In review", I need to check that my Z weight column totalities a hundred.

Should I do this on my aplication by modifying my aplication code? do you know where should I do tihs?

Or should I use a badi and link it to my template?, do you know which badi and how should I link it?

I guess it could be better the first option but I'm all ears to any suggest.

Thank you very much.

Nico.-