How to get accurate dimensions

I have played around with the decimal points in options, but when drawing, can only get measurements like this.
4.250mm  4.500mm  4.750mm 5.00mm.
I need more precise measurements. How can this be done ?
Mike.

Have you set the precision as well in Units as in Dimensions?
Maybe the entities you have measured indeed do have these lengths. Drawn with snap on grid?

Hi Tried all the various settings for dimensions but still can not get the type of measurements I need, such as a drilled hole size of 9.1mm.  Nearest I can get to that is either 9 or 9.25.
I need to get a piece of metal laser cut to precise dimensions . I am nearly ok but not quite there yet .
Mike.

Here is a sample file, no problem at all.
hole9point1mm.dxf