before save logic hook does not update calculated field, by design?

I have a discounted_unit_price field and an extended amount = discounted_unit_price * quantity.

If the discounted_unit_price is set in a before_save logic hook to prorate the amount, the extended_amount is not updated.

Is this by design?

thanks,

FrancescaS

Sugarcrm Pro 7.6.2.2