Log displays "count only below" volume incorrectly

[AlisterH]

If I use "Count only below" the log shows it as "above volume":

===========
16:38:30
Polygon Layer: New scratch layer1
Height Layer: existing supertin.existing supertin out
Base Line Option: Manually enter base level
Counting Option: Count only above (eg. stock pile)
Step Size X: 0.2
Step Size Y: 0.2

Polygon Id: -17
Above Volume (m3):106385.3
Below Volume (m3):0
===========
16:40:18
Polygon Layer: New scratch layer1
Height Layer: existing supertin.existing supertin out
Base Line Option: Manually enter base level
Counting Option: Count only below (eg. gravel pit)
Step Size X: 0.2
Step Size Y: 0.2

Polygon Id: -17
Above Volume (m3):92727.7
Below Volume (m3):0
===========
16:45:22
Polygon Layer: New scratch layer1
Height Layer: existing supertin.existing supertin out
Base Line Option: Manually enter base level
Counting Option: Count both, above and below (cut/fill)
Step Size X: 0.2
Step Size Y: 0.2

Polygon Id: -17
Above Volume (m3):106385.3
Below Volume (m3):92727.7