monkey.jungle base not working as expected

docs suggest this should work

base.sourcePath = source;source-default
venusq.sourcePath = $(venusq.sourcePath);source;source-rectangle-240x240-a

I have common source in "source" 
common but not device specific in "source-default"
device specific (venusq) in "source-rectangle-240x240-a"
change the monkey.jungle to 
base.sourcePath = source;source-default
venusq.sourcePath = source;source-rectangle-240x240-a
and it works.. is this ok? i'm using SDK 4.2.3