After each 7 day break, can the time be changed that you take the next pill packet or does it have to be the same time every time?

It's best to take it on time, or follow the usual rule and take your pill within the hour window you have for being late (12 hours or 3 hours) and shift it bit by bit. Of course another way of doing it is starting your next pack early depending on what time you want to start taking your pill. So if you take it at 5pm and want to start taking it at 9am, take it 8 hours early and continue taking it from that time with the rest of your pack. Taking it early is not risky like taking it late can be.

If you want to change your time to later you can always shorten your break week and take your pill on your new later time on the 6th day of your break instead of the 7th

It depends how much later. If it's less than 12 hours later you can switch right away. If it's more than 12 hours later it's considered a missed pill. Which would leave you unprotected since it would be the first pill of the new pack.