The intent of the section is to clarify that certain additions and alterations must comply with the applicable mandatory portions of CALGreen. E.g., building additions of 1,000 square feet or greater and/or building alterations with a permit valuation of $200,000 or above shall comply with CALGreen. If the addition and/or the alteration (tenant improvement) does not meet the criteria above, then the project is except from CALGreen.
If they used just "and" it would exclude many projects.
If they used just "Or" it may, in some minds, exclude some projects
They are trying to include as many projects as they can