Hi, Terry
You are correct, those coordinates shown in the FS2004 in Slew mode are rather crude.
I use what I think is a very simple method to get the position of the aircraft to up to 13 decimals.
I use ExcBuilder to give me the position. ExcBuilder is a "one-pony-show" prorgamme that makes exclusion rectangles, freeware, that takes no space at all, and reads the position of the aircraft in FS2004 and allows you to, then, copy and paste the coordinates somewhere else.
Please note I didn't ask you WHY you need this, as it is none of my business, but pretty much all the tools that locate objects onto FS (by generating a bgl) do the same thing as ExcBuilder.
Please let me know if this helps.
Fern
fernmarques@yahoo.com