2x1 is wrong. January seems ok. But february misses the back of the 1st. March the 1st page is not right. It's not possible to print with the correct sides matching.
This is the setting I am using in Adobe Acrobat Reader for the 2x1 files. You need to flip the numbers here otherwise it will put them side by side instead of 1 on top of the other.
Can you let me know how you are printing? It seems to line up correctly for me on both months if I use the above setting.
For Feb, the back of the Feb 1st is the 3rd page (that describes how characters level up). It should line up correctly.