Maintenance Ratio does not get updated

My AC maintenace ratios are not updating, even if I had no flights for 3 days and the ACs were grounded. The strange thing is that even positive maintenance ratios are not reduced. It's exactly same values as in screenshot for over 5 days. Though, the condition keeps dropping. What's wrong?

The maintance ratio is simply telling you if you've left enough room in the flightplan to theoretically maintain this plane properly, it changes if you change the flight plan. If you leave room for maintenance daily that should be enough. With over 100% maintenance ratio you are good and if you are under 100% it won't be enough in the long run. The condition then will be the consequence. It decreases if the plane is in operation and it increases when it had a pause for maintenance. The condition will be updated after the maintenance break, the moment the plane starts its next flight. With a maintenance ratio over 100% your plane should reach a condition of 100% at least once per week. Usually it reaches 100% condition daily if you scheduled every day the same.

That makes sense. Thank you Roddi!