Originally Posted by
amz500
According to me the booking classes do not change even if you have 1k. It still remains Y or B, which are so expensive that I might as well pay for Business class.
The Y/B fares are required for miles based upgrades, not SWU upgrades. The use of UA SUW's on LH is not limited to only Y/B fare codes; they can be used on several lower fare booking codes to upgrade to C as well as for upgrades to F from J/C/D/Z. There is a long thread in the UA forum on the use of SWU's.