SmartDraw allows you to specify the level of precision in your floor plan. For architectural scales, the default level of precision is 1/16 of an inch, but you can get as detailed as 1/64 of an inch. To set your desired level of precision, click on Precision under Units & Scale.
For metric scales, you can specify the number of decimal points you want. First, set your scale to a Metric option and then bring up the Precision drop-down to set your level of detail. The default is set to two decimal places, but you can specify up to 6 decimal places if you need to.