As they were unable to rent/lease all the other floors to a single tenant, they have decided to break them up into smaller "packages" that would make it easier to lease out to a number of smaller tenants (e.g. instead of, say, a package of 10 floors they may split it into 2 lots of 3 floors and 1 of 4 floors).
It involves a fair bit more work and hassle letting it out in smaller pa kages, but makes it easier to acquire tenants.
Hope this helps
PS: I might rent a car when on holiday but a car regularly used by a travelling salesman may well be leased by his employer from a hire car company.