We had a rat get in through an opening under our front steps and it started chewing our water pipes. Exterminator said he wasn't even living in the house or was going in and out to get food so it didn't care at all about the traps we set. This went on for 2 weeks and every leak involved ripping out drywall and repairing the plumbing. Half the ceiling in our basement was torn out by time they sealed the hole and the rat could no longer get in. Thankfully insurance paid for it because the total cost of mitigation (tearing out drywall and removing debris), plumbing repairs, and then replacing all the drywall and painting and replacing carpet that got wet was like $60K. From a rat. Crazy.
It makes more sense to me that a model would underestimate a fairly variable phenomenon in an area where it occurs more frequently and overestimate it in an area where it's much less frequent than most places, than vice versa.
Since models don't account for every fine detail that causes lightning to occur, they just look for the typical parameters.