Thank you for your reply.
So here is the math I did:
7 month of "old fashion" full time: 28 weeks*37.5 hours/week=1050 hours.
You can't count hours in excess of 30 hours per week. The hourly equivalent of 28 weeks of "full-time" ("at least 30 hours per week) is 28 weeks * 30 hours = 840 hours.
then 52 weeks-28 weeks=24 weeks, 24 weeks*30 hours=720 hours.( the hours I need to work as part time). Now I have worked 442.5 out of 720 hours already( some times work one day a week, some times seven days a week),
I have no idea what this means - "some times seven days a week." Doesn't matter how many days a week, only matters how many hours per week. If you work 2 hours a day, seven days a week, that's only 14 hours. If you work 8 hours a day , 7 days a week, then it's more than 30 hours and it's not part-time.
since the policy changed to 1560 hours and one year experience, isn't it means I need only 1560-1050-442.5=67.5hours?
Well... There is no stated policy of 1560 hours. CIC is no longer stating an hourly equivalent. The only stated policy is 12 months of full-time work (or the equivalent).
A week ago I would have said "No, Sorry - full-time is full-time only. If you want to count your full-time weeks in hourly terms, you can only use 30 hours per week." But it looks like the instruction guide was modified again on January 17, and the language regarding not counting hours in excess of 30 hours per week has changed (or more accurately, disappeared). I don't know what this change means.
My advice would be to make sure you work your 720 hours of part-time work before applying, because you would really hate it if you were refused for the lack of a couple week's work...