The difference in the 25c is quite obvious once you see it! And it looks like the 2c may be OK as well (or rather not) , but the 15c???
The only reason to change the design was that the change in lay-out from 100 to 200 per counter-sheet. I would say hardly any reason to re-engrave stamps consideringit to involve just 3 face values and meaning a lot of work for Vaquer - several months of work that is!