This varies on a Park by Park basis - need to know size (you could have a full time handyman which is cheaper than one operating job to job), type of Park (55+ communities will generally have lower repair %), tenants screening practices (do you run a Mobile Home Park or Trailer Park?). I have seen all Park Owned Home (POH) Parks have 30% expense ratios, and then others with 60%. It really is a case by case basis.
Most here prefer to have all Tenant Owned homes to avoid all the management overhead and downside risk associated with mobile home repairs, in which case your expenses for infrastructure repair are typically 5-10% year over year. And if someone acquires a Park with many POH’s then strategy #1 is to sell them to the tenants.