"Within a period of about 50 years, a bank barrow was built over the enclosure. It was a 546-metre (1,791 ft) long mound of earth with a ditch on either side; the parallel ditches were 19.5 m (64 ft) apart.[9] Many barrows lie over graves and are monuments to the deceased, but as the barrow at Maiden Castle did not cover any burials, it has been suggested that it was a boundary marker, which would explain the limited human activity on the hilltop for the 500 years after the bank barrow's construction".
Think there was a closing bank barrow on the Dorset Cursus, what does strike me though as to whether barrows have burials or not is the geographical location, my feelings (note subjective) as to Somerset barrows is that they belonged to settlements and had burials, trackways followed the line of barrow cemeteries - doff your hat as you walked by....