Maxred, you misunderstand. We are in 'violent agreement'
except that on N-register there are LESS requirements than you thought.
There is no European style 'tag' for 'on condition' for FAA regulated private light aircraft. ALL engines must be inspected annually by the same simple procedures, regardless of time since overhaul. Manufacturer recommended TBO has no regulatory standing. As such, neither engine operating time nor calendar time since overhaul make any difference to FAA mandated inspection or maintenance protocol - regardless of whether the engine has 25 hrs and two months since overhaul or 3000 hrs and 30 years. There are no special regulations and procedures for engines having exceeded any particular time or calendar period since overhaul - hence the engine would not be put 'on condition'.
In addition, 100 hr inspections are required only for FAA regulated aircraft in commercial service. Otherwise an annual inspection is the only FAA mandated inspection to maintain airworthiness of a privately owned aircraft, and FAA regulated private light aircraft are not required to document or submit a maintenance program.
And finally, the manufacturers maintenance manual is a reference document under the FAA regs, not a legal document. Only the 'Airworthiness Limitations' section (if it exists) is regulatory in nature. The required scope of an annual inspection is regulated by a specific FAR which does not reference commercial data such as recommended procedures within the maintenance manual. The certificated mechanic (A&P IA for an annual) must satisfy a very generic and simple FAR, something like the MOT requirement for a UK car. Otherwise, The A&P and owner can use the manufacturer's maintenance manual procedures as a reference, at their discretion, but need not slavishly follow them. This has an advantage when they have been proven wrong over time - and since FAA certified aircraft do not have a government appointed commercial 'support' organization to mandatorily update the maintenance manual decades after manufacture, over say 50 years that becomes even more often the case than it is with a newly certified aircraft. Regardless, best practice is determined by the owner and certificated mechanic.