Can seven-day hotel chains check in after midnight and check out at six the next morning at half price?

There is no fixed reply to this. This depends on the specific discount given to you by the clerk on duty or the lobby manager on the day you check in.

1. If you make a hotel reservation, you will be charged a full day's fee for checking in in the early morning.

2. It is a special case to check in after midnight and check out at 6 o'clock the next morning. It depends on the hotel lobby manager and clerk to give you a discount. If you want to check out at 12 or even 14, there is definitely a full-day charge. Hotels usually check in at 7: 00 a.m. and at 7: 00 a.m. the day before.

As you are only staying for 5-6 hours, I suggest you check in by the hour.