After importing my dwg file and re scaling using the tape measure, sketch up asks and i confirmed to rescale whole model but only the component I rescaled is correctly changed and the others are changed but not correct. Sometimes its 3cm off and sometimes 3metres off (incorrect).
I tried changing the display preference and units (in meters its also incorrect). I tried selecting all and just selecting one component whilst measuring, I also tried exploding first and then also without exploding. Within a group and also then not within a group. And in all of these cases the measurements dont match the actual floor plan.