Civil 3D Service Pack 4 & Hyrdroflow SS - Broken HGL Calculation

[ryanboshart]

I have 2 computers with AutoCAD Civil 3D installed.  One computer has Service Pack 2.1, the other has the most recent Service Pack 4.  Running the exact same Storm Systems file, the HGL calculations are vastly different.  For instance, with the Service Pack 4 computer, increasing the pipe size for certain pipes will make the HGL upstream go up (this is not correct).  However, on the SP 2.1 comptuer, making the exact same change to the same pipe makes the HGL go down (as expected).

Somewhere between SP 2.1 and 4 there has been a change to the HGL calculation within Hydroflow Storm Sewers.  Can Autodesk verify this issue?

I have attached the file in question.  To mimick the results I have, run the file as is.  Note the HGL on lines 17-end.  Then change lines 16 & 17 to 24" diameter pipe and re run the file.  Compare the results.