I'm using the Block symbols in the Block Schematic template. I've tried to use and "not" use all of the different snaps. I've found that by increasing the precision to 5 decimal places, I can see where the problem comes in.
If the grid is set to 0.098" then symbols should be drawn to that exactly. Over a distance, you can see how the connectors start to get further away from the grid points. You can use the Dimension tool to see that the connectors are slightly less than 0.098". I was unable to get the grid to stay exactly at that dimension, and I don't know that all symbols will exibit the same behavior.
At this point, since I will need to check and possibly modify all the symbols I use, I am going to use AutoCAD. I've been using it for years and can really fly with it, even if I need to recreate all my own symbols. I don't really need all the reporting features of Stardraw AV, so thats really not a loss for me. And, if I remember correcly, AutoCAD can do most of those features with additional programming.