In a case where there are a number of flash boundries that are low such as 1.1, 2.3, 5.5, etc. would it be permissable to round up to maybe 6. I imagine it would have to be written into the policy something on the order of any distance under 6" will be established at 6".

Nothing prohibits you from putting a larger distance than what's calculated on a label.

In fact, when you do, it's easier on the user because it's more uniform from one panel to the other. If you can use the same distance as the LAB, then you've reduced from 4 different distances to 3.

Plus, if you make it reasonably large (4' or 6'), it prevents the visit from people having nothing to do in the area while work is being done, as you're must have some kind of barrier in place to indicate where these people should stand.

As Vincent says, there is nothing preventing you from increasing the arc flash boundary, and there are several recommendations out there to do just that.

I also make the minimum arc flash boundary the limited approach boundary. I also round the arc flash boundary up to the nearest foot.