English to Spanish Other Law (general) Terminology

Hi dear all,

I am translating some texts on differents standards. I come across different sentences such as:

Description *SHOULD* be in a clear, concise, logical, readable format.

All regulatory requirements *MUST* be met in full.

the work*SHALL* be contracted out to competent environmental consultants.

The problem is with these modal verbs. In everyday English, we use SHOULD as s"OUGHT TO" (a piece of advice..you should do this, but you don't have to).
SHALL is mandatory and MUST too.
From my experience translating technical texts with legal connotation (I mean standards, for instance):

SHALL is deberá (indicates obligation)

MUST is not so frequently used (due to the fact that is not so formal as SHALL) but it also means "deberá"

and

SHOULD (although its common meaning is "debería") is "deberá" as well as SHALL. We can't give room for someone to do o not to do something from a Standard. In those cases, CAN or MAY is used to express the possibility that you can do it or not and there's no obligation.
For instance, in the case:
Description *SHOULD* be in a clear, concise, logical, readable format.

the translation is:

*Se deberá presentar* una descripción clara, lógica...
Because we can't say: " se debería" and let the person reading this Standard not do what he HAS to do.

Am I right? I need some explanations, please :)

Thanks!