So some further information about Schedule A. It could be asked based upon a YES in any of refusal (statutory) questions. But it was asked of many people with all nos as well.
By "gaps in background" usually people don't know that it actually means something over looked.
In most forms CIC states "since 18 years of age or last 10 years which ever is most recent". So if it has been more than 10 years since you were 18, you would just input those.
I heard from some lawyers description that their system needs it since the age of 18. So every one who misses that, receives Schedule A, even again if they make the same mistake.
And this fits perfectly for all cases i know which still received Schedule A while they didn't have any NOs in statuary questions.
Moral of the story, provide all history since the age of 18, period. Besides there is no harm in doing that.
Hope it is useful to others. Good luck