ACBC doesn't give the user any tricks to force a particular level of an attribute to occur more times. ACBC's alternative-specific designs are meant to oversample attributes and levels that seem to be more relevant to respondents. Whereas, our CBC software provides a way for power users to crack in and modify the experimental designs.
I have found that ACBC's alternative-specific designs can struggle if multiple tiers of alternative-specific attributes are used, rather than just a single tier. Meaning: some attributes are dependent on the level(s) of another attribute, which in turn is dependent on the level(s) of a third attribute.