Agreed there doesn't seem to be a nice (lol) mechanism to reset niceness values.  I'd not seen `declare` as a bash built-in before but I think I can see what it's doing.  Though I think it's equivalent to:

    command "nice -n $((-$(nice))) service..."

making use of bash's `$((...))` notation for maths.  This seems more readable to me, but I don't feel too strongly about it.