Can ITM be substituted for LITM in code fetches and SQL?

Hi,

I've seen this so commonly that I am already on the doubt of it being actually an issue.

Some of the developments and folks that I have worked with widely use field 2nd Item Number (LITM) as the only reference, to the point of excluding elements like ITM and KIT from custom tables. I've always thought that, from an entirely technical perspective, the norm is supposed to be the usage of ITM, as it is the primary key in many standard tables.

Is there any documentation that indicates that ITM is expected to be used in the backend instead of LITM for code programming (fetches, SQL construction, &c)?