I've the same problem as you do and called 雪印 and was told 2 are basically the same except that 日本雪印are subject to 日本厚生省standard and
雪印思敏兒 are subject to 世衛WHO standard! But she didn't tell me how different are they but I personally prefer WHO standard and would suggest you finished off Pure first and then switched to 雪印思敏兒. If your baby is OK with that you can keep feeding otherwise you might sell or even consider donating the unopened cans to the food bank: http://foodbank.sjs.org.hk/HowToHelp/chi_fooddrive.htm