You've just destroyed my faith in the .xpos and .ypos variables.
Maybe a better way to go is to have nested global and local locations, so that the global position returns a grid with 32000x32000 per square, which is then subdivided into the local coords.
This behaviour of .xpos and .ypos is not new. It has worked this way for larger fields for a while now. Adding yet larger fields doesn't change anything except make it more obvious that the granularity of these change with field size. Many various options were discussed in detail at the time this was addressed including your suggestion and the current behaviour was settled upon for various reasons not the least of which is a general aversion to providing bots non-local information. The decsiion not to remove them entirely was made msotly for backward compatability reasons.
As it is, it still allows ant bots to rendevuez, F1 leagues to use exact positioning, etc. I have no plans to change this. I would however, be very happy to remove .xpos and .ypos all together if peopel would let me...