I have iRules and Parameters set up in order to specify certain UC & UB sizes in my material list through part description.
E.g - if the parameter UC HEIGHT = '419' the parameter UC DESIGNATION = '356x406x393'
(Iv attached a snap shot of my rule browser)
For 27 out of 30 Beam designation sizes the rule works, my parameters update and the part description updates accordingly. For some reason certain rules dont work. When i created the rules all i did was copy the text in the rule browser and change the values accordingly.