2.1.629 Part 4 Section 220.127.116.11, cfvo (Conditional Format Value Object)
a. The standard describes @val as type ST_Xstring.
Office assumes that @val is restricted by valid Conditional Format Formulas as defined in Formulas ("[ECMA-376] Part 4 §3.17; Formulas").
b. The standard does not state any restrictions on the value of the type attribute.
In Office, if the parent element is iconSet, the type attribute cannot have values of min or max.