@ Dr Reem
Thats the reason, i wrote abt RE-VALIDATION, although i don't understand y u need to go somewhere to revalidate it. You may consider paying me for this service by donating some money to charity of your choice and praying for our success in this immigration process, or at least give + 1 every week for rest of ur life,
as otherwise ur application wud have been certainly rejected as they read the BAR CODE to save the data in their system rather than manually entering it (unless its manually filled)
Technically, it should be most recent travel on top but if there is no specific instruction u may opt for any sequence....... the instruction will either be on "travel form" or CIC guidelines available on their website. Again, how long it will take to reverse the order, not more than 2 mins unless u r an avid traveler.