There are mandatory heater pressure checks every second year . and certainly with vp props rather expensive propellor checks at about 3 year intervals. Then there are all the engine accessories which each year will produce some sort of defect which will require an overhaul or replacement. Then there is the airframe which will gather defects and corrosion, avionics which may require attention ,fuel tanks and tyres to replace,
and engine cylinders which may require replacement due to cracking and other defects.
With all these indeterminates it is unlikely you will get much more information on costs other than the cost of an annual inspection and cost of air test and paperwork and fees for a CofA.
these will be very poorly correlated with actual cost of maintenance.
Hope this helps.