The best way to do what you need is to break your Easel project into two separate projects. Draw the box and the lettering first in one project and rename it (with a name like my project - small bit) to create the first bit size file then copy it and rename it with a name like "my project - large bit"
Then you can set the depths of the lettering in the "small bit" file to the depth you need and leave the depth of the outline box at zero (so it does not cut)
Then edit the "large bit" file to change the depth of the lettering to zero and the depth of the profile cut for the box outline to the depth of your material.
Then zero at the lower left of the material and run the small bit file. When it is done change your bit and be sure your zero is in the same exact X/Y at the lower left of the material (with the new bit zeroed to the top of the material) and run the large bit file.
This will work much better than trying to use the rough/detail option for letters and profile cuts.