do i need to ask for a variation (sp)

[jaytravis]

my little boy will be 4 in oct and will be starting fulltime nursary at school also i childmind a little girl who has just turned 4 and will; be in school full time is it right that they will both be classed as over 5 as i can mind 2 under 5 on my certificate
so if someone came to me asking to look afetr two 3 yr old s could i do it or would i need to ring ofstead and ask them for a varitaion
]sorry if sounds confusing i havin been gettting everything ready for this eyfs and my barin is fuddled lol
thanks

[Chatterbox Childcare]

Your son still takes up a full time under 5's space as you are responsible for him - holidays, sickness etc...

If the little girl goes to school for 10 sessions a week she will be classed as over 5 and you could have the 3 year old or another under 5.

[littlegems]

WHAT????:panic:
I am now confused, and very worried. hoping i have misunderstood!
i have 2 kids of my own one who is 2 and the other 4 but he starts school next week so i thought as soon as he was at school full time he counted as over 5? is that not right?