I went to Walmart today and I can now answer my own questions. The SKU on the new 10K syn. is the same as on the older ST syn. so that means that the original ST syn. is now labeled for 10K (whether or not the formula has been upgraded is unknown). The new 20K syn. is the 'Advanced syn. and has a new SKU. The 10K stuff says "10K or one year whichever comes first" and the 20K stuff says "20K or one year whichever comes first"....so both are limited to one year of use. The 10K stuff says "Superior Wear Protection" while the 20K stuff says "Maximum Wear Protection". The 10K is $14.47 and the 20K is $16.96 for the 5 qt. jug...or 50c a quart difference....