The Bianca is delivered with an offset of 10C. That is the brew boiler is 10 degrees hotter than the displayed temperature. This works well for the review machine Dan has, but it wasn't right for me. I've reset mine to 14C, and I'm getting very accurate performance without any flushing. I'd be interested to hear what other owners have found.
I've been somewhat, although not closely, following the various adventures PIDers have had, from retrofitting PIDs to stock Lineas, Silvias, Domobars, and Renekas in the early aughts through the first DB E61 machines to the current crop of DBs featuring integrated, saturated, and thermosyphoned groups. The hard truth is that people need to use different offsets for the same model machines. My guess is that this is one of those chaotic thermodynamic things, where even tiny differences, well within manufacturing specs, in the sensor position or positioning of the group, can amplify into much bigger differences in the offset.
I've posted a how to
on calibrating the offset using flash boiling without needing a Scace or similar temperature measuring device. This may be helpful.