PIDs 0101 (monitor status since DTCs cleared) and 0141 (monitor status this drive cycle) are both returning the monitor status, however as per the specification only 0101 differentiates between spark ignition and compression ignition, hence the bit-to-monitor-mapping is different.
As per the standard documents (and Wikipedia1), this distinction is missing in 0141, so how am I supposed to interpret the result of 0141 on a compression ignition vehicle then?
In the latest version of the standard (SAE J1979DA-201406) – which I have since bought – they have clarified that bit by specifying B3 as injection bit for both 0101 and 0141. Thus this question has been solved.