There is a weight limit even on "Pcs" system as well.

Have a friend is moving back from FRA to USA and I was planning a MR to carry 3 bags for him. Called UA 1K desk this afternoon and this is what they told me.

1) As 1K & 1P, we can check in 3 bags each and maximum weight per bag is 70 pounds.
2) Over weight fee is US$381 per bag if under 100 pounds.
3) If bag is over 100 pounds, they will have to go via air-cargo and not as "check-in" bag with ticketed passenger.
4) If I check in 4 bags, the 4th bag will cost US$127 per bag for up to 70 pounds.
5) Bag allowence is based on seat, so if I buy 2 seats, I can check in 6 bags.
6) I will earn miles on the second seat purchased, but I will have to contact MP desk for the credit after completion of the trip.
7) Earn status mileage bonus and other promos with 2 tickets? 1K resv agent does not have the answer for this and I haven't check with MP desk.