I have the Steam versions of several packs, but am unable to comment on your DLC there, so I hope you don't mind me asking here.
Is there no 'World' water and snow tiles for inside corners? The 'B' tab has several additional items not in the 'A' tab, but those appear missing.
Edit: Also, some of the tileA2_world tiles, don't auto tile correctly. It seems that 'tileA2_world.png' and 'tileA2_outside.png' are visually identical files.
Thanks for your time.