In calibration we tend to use Movie/Cinema mode because they are usually the most accurate pre-set picture modes. When we calibrate, we want to avoid making drastic changes so using Cinema mode makes that easier. Technically, the only difference between your day time and night time modes is that the day time mode should be brighter than the night time mode. The white balance, gamma, and colors should be the same. If he were to calibrate using the living room mode, he may be able to achieve the same result, but it would take much longer and require more drastic changes to the controls (and he may end up charging more). If you feel the day time mode is not bright enough, simply increase the backlight setting. This should make the display brighter without messing up the brightness (how black the blacks are) and contrast (how white the whites are).
As far as his spectro thing... I'm not sure dude. Did you get an ISF calibrator or some other guy?