No, the OBU never calculates a toll abroad. The value in the top left-hand corner of your OBU display always says “TOLLFREE” when you are abroad. This means that no toll is being incurred at that moment.
However, you might see values on your OBU display (in the bottom left-hand corner where the covered distance subject to toll is displayed and in the top right-hand corner where the total amount of kilometres driven is displayed). Those values do not correspond to any toll incurred but appear due to a known behaviour in the OBU’s memory function: after every reboot of the OBU (but not waking up from sleep), the OBU may display an erroneous value from its memory. Satellic is making every effort to resolve this problem.