BPGM also has a mutase and a phosphatase function, but these are much less active, in contrast to its glycolytic cousin, phosphoglycerate mutase (PGM), which favors these two functions, but can also catalyze the synthesis of 2,3-BPG to a lesser extent.
While BPGM has both mutase and phosphatase activities, they are less active than its glycolytic counterpart, phosphoglycerate mutase (PGM).  However, PGM can also produce 2,3-BPG, albeit to a lesser degree.