Decimal scale is in the same format as the Input. All Decimal values are rounded to the specified number of decimal places. Default value is 6. For example, 4.6059556 will be rounded, displayed, and/or returned as 4.605957.

You can adjust the default precision for decimal values. In the brms.properties file, set the Studio's decimal scale: 
decimalscale=2
When set to 2, the example's rounded value is 4.61.