Does the XPS 15 have a 400 Nit Screen - Dell will not confirm?

Please can you help because Dell cannot.. This Dell spec page { http://www.dell.com/uk/p/xps-15-9530/pd#AnchorZone2 } for the XPS 15 says the screens are 400 Nit Brightness however, when I go through the configuration here and click on "help me choose" I get this http://www.dell.com/learn/uk/en/ukdhs1/help-me-choose/hmc-lcd-display-3d-consumer then click on "compare side by side" ... it says the XPS 15 has only 270 NIT brightness. I spoke with a Dell rep today and he said it was 400 NIT, I said great can you please put that in an email and he refused for legal reasons.... ??? it either is or isny 400 Nit, if unsure surely he could find out? Can anyone who has an XPS 15 or better anyone from Dell please clear this up, I need a 400 Nit screen and nothing less. Does the XPS 15 have a 400 NIT screen? Many thanks