K value setting and LR 'as shot' temp.

Whilst playing with different ways of handling color temperature on my 5d (classic) and comparing my yongnuo 560iii with my 430ex I, I noticed that although I chose a K setting of 6500 in camera (that resulted in a fairly neutral histogram for the ostensibly neutral object I was shooting), when I pulled it into lightroom, the 'as-shot' temperature value was 5500. I'm baffled as to why this might occur.

Any ideas ?

This is what Eric Chan, the main designer of LR/ACR once wrote in response to a similar question:

The translation is that WB is a pair of multipliers for the red and blue channels. When you dialed in 6500K the camera wrote in the Exif something like "multiply the reds by 2.4 and the blues by 1.3" and those are the values that the built-in Raw converter used to make the embedded jpg. And LR also reads the Exif and uses those multipliers. But this operation is done after the camera profile is applied and the LR profile is different from the Canon profile. And LR and the camera worked in opposite directions. The camera said to itself "Chris wants a WB for 6500K light; now what multipliers applied on top of Profile X would produce the desired neutralization? I'll use 2.4 and 1.3." And LR said, "Well I have to use 2.4 and 1.3, so on top of Profile Y, what color light would be neutralized?" Add to this the fact that color temperature is not a single color, but rather a range as seen below, and it's no surprise that LR comes up with a different number.

I'm not familiar with using the Yongnuo flashes, but as a "starting point" I'd set the camera to the "Flash" White Balance, or to the Auto White Balance if the camera recognizes the flash, but I'd also shoot in Raw so that in Lightroom you could quickly select the whole set and just adjust the WB for everything.