funsmpls

Hi....I'm planning a trip to Europe this fall and can book any star alliance carrier. Considering - depending on airline - some booking codes carry 0%, 50% 75% or 100% credit, what's the best way to figure out the booking codes on the different fares? For example, on the Air Canada web site, it will show a code on the booked itinerary and I'm wondering if that is the code for that fare? Is that the actual code to determine the credit you will receive? Thanks