Does it means (theoretically) that if my DC got (let's imagine!) top score on test for certain oversubscribed school placing that school as 2nd choice on CAF it will be slim chance to get into that school because all places to that school are gone after 1st round of allocations even to pupils scored lower than DC?
I suspect you are confusing the 1st, 2nd, 3rd choice format.
Even though you are being asked to advise the LEA via the CAF of your school choices as Hermanmuster has said only ONE of those will be offered on allocation day in March.
By placing the 'top scoring test 'school 2nd (As in your example above) you have basically advised the LEA that you would prefer the school which you have placed above it, more.
If the LEA have places at your first choice school and your DC meets the criteria, they being nice kind hearted souls, will oblige you and offer you your first choice.
Your other choices will not be referred to.
These only come into the picture if the LEA cannot offer you your first choice. Then they each in turn will be looked at in the same way as above, until a school that can offer you a place and also one that your DC meets the criteria for is available, then this will be offered.
If you are a yr6 parent, Your LEA should have already sent you a 'Guide to Secondary School Admissions' booklet. All of this is fully explained in there. Alternatively you could check the guide out on the LEA's website. Or this
also gives an overview.
If our 1st choice school will not offer and if paragraph above is correct -> welcome to sync school!
It will be for the first school on your list that can offer you a place.
What are chance of getting offers from le't say two schools in March?
You will only get one offer of a place at the beginning of March.