Yes. For wood-fiber insulation boards — including Steico, TimberHP TimberBoard, and Hempitecture Plant Panel — the correct system is always Earthaus Bond Plaster as the base, regardless of which finish you plan on top.
Do not apply PHL Binder scratch/brown coats directly to wood-fiber board — Bond Plaster is the approved base for this substrate family.
Because board products vary, always do a small adhesion pull test on the actual board before full application.
The board must be rigid, properly fastened, clean, and dry.
Once the Bond Plaster base has cured, continue with your finish system per its installation guide. Bond Plaster replaces the Base Plaster step for this substrate family. Do not apply Base Plaster in addition to Bond Plaster; go directly from the cured Bond Plaster coat to your finish system.
See the Bond Plaster Installation Guide for full application details.
For the complete layer-by-layer systems, see the Wood Fiberboard Interior Wall System Guide and the Wood Fiberboard Exterior Wall System Guide.