In terms of language, I would go for:
Working hours duration time should be *below* that defined *by* parameter default.time.
Working hours duration time should be below that defined by parameter default.time.
If you do mean the value (please see my comment on your question), then you need
Working hours should be *less* than those defined *by* parameter default.time.
Working hours should be less than those defined by parameter default.time.
