By dialing in additional base iso, all you're really doing is delaying the point at which auto iso will kick in and start to adjust itself upward, since you've already surrendered that amount of lower iso from the get go. I don't see where anything constructive has been accomplished. You might as well keep the camera at base iso and only surrender the lower iso values if and when necessary as determined by the auto iso function .

Here's the way I look at the +/- adjustments for the auto minimum shutter speed function. I look at it as a function of the photographer's confidence in his hand-holding ability and technique. Since the 0 setting is the standard repciropcal setting, adjusting away from from the 0 setting would be because for some reason, you feel that the standard reciprocal setting would not be appropriate. For instance, if you were using a VR lens, you might feel that you could comfortably squeeze another stop or two from the standard recirpocal setting, which would result in using the -1 or -2 setting. Or perhaps you feel that that you have really good hand-holding technigue or perhaps a tree to lean against and could also squeeze another stop or two from the reciprocal. On the other hand, you may feel that for whatever reason, your technique is not up to the reciprocal standard, and therefore need to increase shutter speed by a stop or two to produce acceptible results. Now you might use the +1 or +2 setting. Another reason to deviate from the reciprocal might be because of the high resolution of the D800/E, you feel you need to shoot faster than the reciprocal.

Russ