
I bought this block about 10 years ago - the top pair is Type III (#33) and the bottom pair is Type II (#32)
The various types of the 10c 1857 are spread out around the plate, so various pairs/strips/blocks are possible.
When the plates were being made, I fully expect the printers didn't think of the various entry reliefs as different - they were all 10c stamps. I expect they knew that they had different reliefs and that there were 'microscopic' differences between them, but they probably had no concern at all about which was which on the final plate. They were simply doing the best they could to fill orders of these stamps. The various types were discovered and classified by philatelists years after production.