Get an oven thermometer so you know the temps are accurate
And then...follow this...it's from the magical butter machine website, which I use the MB2 with no decarb box
T-C:- Decarb at 250°F (121°C) for 30-45 minutes
C-D: Decarb at 280°F (140°C) for 60-90 minutes
C-N: Decarb at 320°F (160°C) for 90-120 minutes
If you do not have a DecarBox, use an oven roasting bag or on a rimmed baking sheet. Make sure the pan is the correct size so there is not an empty space on the pan. Bake for 30 to 40 minutes, stirring every 10 minutes so that it toasts evenly. When the flower is darker in color—a light to medium brown—and has dried out, remove the bag or baking sheet and allow the herb to cool. It should be quite crumbly when handled.
NOTE: Your oven may not be a precision appliance; this is normal. Most ovens operate on an approximation, average, or range of values for any given temperature. Therefore, calibrating your oven is essential to accurate decarbing and baking. Do NOT skip this vital step, or your sample could be destroyed.
EDIT; Armed with this knowledge, I can make some STRONG edibles...but I use almost 2 Oz per 1lb. of "unsalted" butter