Digital BW, The Print

I'm a real newbie on this so any help would be greatly appreciated. I am attempting to 
setup QTR on my system with my Eye One following the calibration guide. I have an Epson 
2200 using EEM and stock UC inks.  I printed an ink separation page set at 100% and let it 
dry overnight. I've downloaded Profilemaker 5.08 and configured my Eye One Pro for 
reflection with spectral checked. When I bring up the spot measurement window, I have 
the following settings:

Colometric
Color Space - Lab
Observer angle - 2 degrees
Illumination - D50
Delta E
Sample checked

I am at the point in the process where I am trying to discern the hardware ink limit for the 
printer.  Rather than trust my eyes, I'd prefer to measure it. It's at this point that I'm 
confused.  Do I start measuring at 50% and work my way up the chart and if so, what am I 
looking for?  If I perform several readings, I get the following:
50% - 22.4
70% - 20.3
80% -17.6
85% -17.0
90% - 16.7

Do I conclude that I've reached maximum at the 85% level as there is not much of a 
difference between 85% and 90%?  

Thanks.

--Joel