Like the central bank with its inflation projections, the OBR will stress not just the most likely path for the budget deficit but also what the chances are that it will be bigger or smaller.
For another, the strategy of UK ministers is to highlight uncertainty, not to seem to be suggesting that they are placing any block in the path of a decision which, they repeatedly stress, is one for Scotland to take.
Everyone has to find their own path, but you can save yourself a lot of time and stress by learning from the best and brightest who have come before you.