I don't believe there is such a thing now (version 8.6) as "Compare Task". Maybe you mean "Distribution Analyzer" which can plot distributions from several tasks either in the same or different plans. Which version are you using?
Yes I agree, that report was a modified version of a "Distribution Analyzer" report. I spent the day learning how to customize that report to suit my project's needs.
The capabiliy of this software is quite impressive. I have to admit, the team that designed & engineered PertMaster did a very good job when compared to engineering results of Primavera P6! Not to mention how well the reporting tools are...... Oracle / Primavera should take notes :)