The temperature below ambient trick will work, but if it has been on for a while with a higher than ambient setting that the FR has ridden up. Set it below ambient and leave it for a while (hour or more) before starting it. If you want FR to drop down faster, set setpoint 5 or so below ambient.
Another option is to set setpoint a couple degrees below ambient and then go to the MIN screen in SETUP. This will run the stoker at the minimum rate and also let the control logic wind down the FR in the background. After an hour or two, put the control back into the round robin by exiting the SETUP menu, and it will run from there. Adjust the setpoint where you want it.
Also, it isn't too cold yet, so you may find you need to use a lower MAX setting than you normally do in the winter (try half the default/normal for your stove). This will limit the overshooting you may see on upward setpoint changes.