Here's what was wrong with the charts in SH1.
As you can see, I've layered Northern Japan chart from SH1 and placed it next to a world atlas page. I've marked in RED where the Longitudes were incorrect in SH1, which always threw off your navigation.
In SHIII the Grids are distorted due to the xy ratio and that makes it difficult to come up with a 4 digit grid easily.
Hopefully, SHIV will get it right.
