'If you are at the top of the easy one, then you should be more than capable of doing the advanced one. At least performing well enough to place you in the midde of the group.'
Not necessarily (as iambored stated). Besides, is there any point in 'trying' when the advanced unit is not what you have in mind?
If you are not seeking a transfer and you know exactly where you are going (in a direction that does not require advanced units of study), then there is no need to take an advanced unit just for the sake of the advanced tag and the possibility of improved scaling.
If you would like a challenge and know that you are capable of undertaking an advanced unit, then go for broke... But if you are not sure then there is little point in doing so.
But, as we can see from your post, other people will not see it that way.