Can I enter a value that is constantly added / subtracted to my measured value? (Offset)

Yes, in the “Settings” you can go to the “Offset Icon” and enter a value that will constantly be added / subtracted from your measured distance value. If an offset value is entered you will see the adequate symbol -  a triangle with plus or respectively minus next to the laser symbol.

If you want to set the offset value back to zero, enter the setting “Offset” and reset it.