X99 WS applies XMP Profile with incorrect voltage

I am using the following RAM in my X99 WS (BIOS 3.10):

Vengeance® LPX 32GB (4x8GB) DDR4 DRAM 2666MHz C16 Memory Kit - Blue (CMK32GX4M4A2666C16B)

Specs of which are:

Warranty         Limited Lifetime
Fan Included        No
Heat Spreader        Vengeance LPX
Memory Configuration    Dual / Quad Channel
Memory Series        Vengeance
Memory Type        DDR4
Package Memory Format    DIMM
Package Memory Pin    288
Performance Profile    XMP 2.0
Memory Size        32GB Kit (4 x 8GB)
SPD Latency        15-15-15-36
SPD Speed        2133MHz
SPD Voltage        1.2V
Speed Rating        PC4-21300 (2666MHz)
Tested Latency        16-18-18-35
Tested Speed        2666MHz
Tested Voltage        1.2V

My X99 WS detected two XMP Profiles, one for 2666Mhz @ 1.2V and the other for 2800Mhz @ 1.35V. Up until today I had been running it at normal SPD, but I decided to enable the first XMP Profile to make it run at 2666Mhz.

So I went in to "OC Tweaker" --> DRAM Configuration and loaded XMP Profile 1 (2666Mhz) , saved settings, rebooted and went immediately back in to bios (I read somewhere that if you dont go back in to bios the PC may hang).

The machine reported that the RAM was running at 2666Mhz, timings were correct 16-18-18-35, but the main DRAM voltage was at 1.35V. This seems to be at odds with the XMP Profile:



I manually adjusted the DRAM voltage to be 1.2V , saved and rebooted and all still seems fine:




The BIOS obviously read the profiles ok from the DIMMs as they are displayed correctly, but it seems to have implemented the DRAM voltage incorrectly.

Did I miss something? I was a little concerned as 1.35V is the upper limit for the memory.