Cura is was over extruding.  Slic3r was fine, so I know E steps/mm is good.  Flow % setting does not seem to do anything. How can I fix the over extrusion?

So I got it initially setup, and it is obviously way over extruding compared to slic3r. Bottom solid layers are way too much, if sometimes it even swelled so much that it catches the nozzle and caused a skip.

My filament diameter is entered exactly. (1.75mm on the nose because octave is very good quality ABS). My extruder steps per mm are calibrated, but that is taken from eeprom and should not depend on the slicing program, right?

The next thing I can think is that the Flow % function in Cura might be wrong? Is that comparable to "Extrusion Multiplier" in slic3r? I figured it might be, so I went to print a single walled calibration cube like I have always done. I did one in slic3r, 0.60 mm nozzle, 0.72mm widths and it came out about right. Then I set Cura to 0.72 vertical shell thickness, no infill, and the print comes out with walls about 0.90mm thick. So I did the math and bumped the multiplier down and resliced. The next cube comes out about the same, 0.89 mm walls (average), which is essentially standard measurement error using calipers by hand. I lowered the flow $ in cura (under the filament tab) from 100% to 80% and got no change. I made double sure I did in fact reslice it changing the skirt setting too.

So the flow % seems to do nothing. What am I missing? How can I fix over extrusion in Cura? I have googled this extensively and not found an answer. Thanks!