Spyder X Elite vs. Colormunki Display brightness difference

I've used the Colormunki Display w/ Xrite puck for calibrating my monitor for many years and have been satisfied, but Datacolor was offering a sale on its Spyder X Elite the other day so I sprang for it.  I recalibrated my monitor with the Spyder and have noticed there is a large difference in brightness between the two programs.

Before recalibrating, I always do a reset to base factory settings first.  I also always set my monitor @ 100 candelas brightness during the recalibration process.  Using Colormunki w/ Xrite puck that requires setting my monitor brightness at 23 for it to read 100 candelas.  With the Spyder x Elite, I had to set my monitor brightness to 15 to read 100 candelas.

What gives with that?  

I turn off all ambient lighting options on both programs and use the identical conditions every time while calibrating.  I just recalibrated using both programs once again and the same thing happened - 15 vs. 23.

I checked the actual color calibrations and they were (for all practical purposes) identical.  To check the colors, i used an Xrite Colorchecker and set up a profile, then opened the file in ACR, chose that profile and saved the image.  I then checked that image using both Spyder and Colormunki calibrations.  I checked four miscellaneous colors (the same misc. colors for each) Here are the readings below:

           With Spyder calibration     With Xrite calibration
Gray            185                                 185
                   183                                 183
                   186                                 186

Med. Blue     130                                 131
                   126                                 126
                   226                                 226

Red              241                                 241
                   99                                   101
                   108                                 110

Green           136                                 137
                    212                                 212
                    118                                 118

So, the calibrations from either are excellent, but I still can't figure out why the brightness is so different.  I would appreciate any input or suggestions as to why this difference is occurring.

Is one set to adjust automatically for ambient brightness and the other not. that would give you a significant difference.

No, they are both set identically.  I did both calibrations at the same time, one right after the other.  So far, I have done three dual calibrations on three different days, one right after the other, under identical conditions, using identical settings with the identical results each time.  


The color calibrations are basically identical to each other, but the brightness difference is a bit concerning.  Currently, since the color calibration was the same, I'm still using my Colormunki Display over the Spyder since my prints work perfectly at it's brightness setting of 24.

Can I assume you didn't have this issue when you changed over?

I use the Spectraview for my workstation and SpyderX on my mac and laptop. I've never used Colormunki.