The other point I also make to people when filling in this form is that every activity has a start point. For example going to the loo starts from the chair you are sitting in when you fell the need and ends there, so should take account any difficulties getting out of the chair, walking there and reverse afterwards, not just what happens when in the room containing the loo.
The second point is that, if when thinking about an activity you find yourself saying to your self 'I manage', then that shows you have a problem you are managing. Taking the example above. If you say to yourself, 'Oh well, I can manage to get to the loo' then you have a problem because, for example, I am fit and well and would never talk about 'managing' to get to the loo, because I just get out of chair, down from a ladder, or come in from the garden and just go to the loo.