Yes your assumption is correct.

For readability this could be better done as a switch statement:

=Switch(

Fields!Gr.Value = "01", "01 Total Score",

Fields!Gr.Value = "02", "02 Total Score",

Fields!GradeLevel.Value = "03", "04 Total Score",

true, "All Levels"

)

Switch evaluates the conditions in order and stops when the first one is true.

The true condition at the end means this value will always be returned if none of the other conditions have been true.

Don't know any URLs but you seem to understand what it's doing anyway.