Those who charge for inspections, do you have a flat rate or does it depend on the porperty?

I recently got a request for a rodent assessment for a house that is about 10,000 sqft, an absolute monster of a house with 6 levels, a 4 car garage (buddy has a McLaren 750S, Porsche 917, Ford GT and a Range Rover!!!), vehicle lifts, elevator, separate chef kitchen, indoor pool...the works! I told the homeowner my standard fee for a more modest sized house, and that I would have to triple that to be able to spend the time at their home and not feel rushed. They did agree and made no issue out of it but it did make me wonder how other people approach this.

Then I found the issue areas and they were about 3-4 times as many as a regular house and the cost reflected that. More doors, vents, cracks, holes, utility lines...it was insane.

Should I have kept the inspection charge the same knowing I would find many many more holes or was it smart to up the inspection charge?