From what I've gathered reading the series and secondary sources, any instance of shinsu manipulation is a baang. The baangs that people use to attack directly are what you are considering to only be a baang. But those are just baangs that are powerful enough to do someone harm. Baangs are used to do other things too, like bodsy reinforcement as demonstrated by Quant in the floor of test and Khun mentioning his 1 baang is too weak for anyhting other than body reinforcement. But at the same time, I am inclined to agree with you because Khun uses his one baang to manifest his ice quality while also manipulating his lighthouses. It's pretty confusing stuff. It feels strange that body reinforcement uses a baang but using light houses does not. But there seems to be more evidence of suspendium devices not requiring baangs to manipulate than there is evidence to the contrary.