Both structures exist and the sector uses them differently than apartments do. Percentage-of-collected-revenue fees in manufactured housing commonly run higher than apartments, often in the 5 to 8 percent range, precisely because the revenue base per unit is small. Per-pad flat fees also show up, and figures in the $20 to $35 per occupied pad per month range are typical in the market, sometimes with a floor so a small park isn't unmanageable. Larger portfolios negotiate down. These are market ranges rather than fixed rates and the specific number depends on scope and location.
On scope, the base fee in a lot-rent-only community usually covers rent collection, lease enforcement, community rules, vendor coordination for roads and common areas, and lot inspections. Utility billing is frequently carved out as a separate item because submetering, reading, and billing is real recurring labor, and in some states the way you can bill residents for water is regulated, so the owner needs to confirm the rules that apply where the park sits.
Collections on resident home notes is a different business. That's consumer loan servicing, it carries licensing exposure in many states, and most park managers either don't do it or do it through a licensed servicer. Don't fold it into a property management scope without someone qualified looking at it.
The scope item that surprises apartment managers most is home removal. When an abandoned home has to come off a pad, you're dealing with title, lien releases, and demolition, and the process for taking possession of an abandoned manufactured home is set by state statute and can take months. Price that as a project fee rather than absorbing it, because you'll do it more often than you expect.