This is my first stab at using this plugin and I am sure I am just doing something simple incorrectly but all I can get this to do is display invalid formula.
My formula is below:
(buffet+china+beverages+coffee+dessert)*guests+delivery
site is http://rwbaz.com/wordpress/catering/
Is is the formula or is it something else, I have literally spent hours on this no and to no avail, any help is appreciated.