For the most part, MSeed mass-position channels have the format VM[0-9] (we will use regex for the format from here on).
However, for Q330 data sets only, mass-position channels can also have the format VM[ZNEUVW]. Because VM[0-9] looks to be a widely-used standard, it is recognized as mass-position by default. To avoid the problem where a datalogger uses VM[A-Z] for non-mass-position channels, however, we only recognizes VM[ZNEUVW] as mass-position if the data type is Q330.
In order to add support for dataloggers that use any format other than VM[0-9] for their mass-position channels, the developer has to add the check explicitly in the code. This can be done in sohstationviewer.database.extract_data.convert_actual_channel_to_db_channel_w_question_mark().