DIshwasher Cycle TIme INcreases by 20 minutes over two years

We have a PDW8800 Seies GE Profile Dishwasher. When we first got it the Normal wash/dry cycle time was ~105 minutes. We normally over rinse the dishes and plateware before putting it in the dishwasher but over two years the cycle time has moved up to over 125 minutes. The unit has Sensing that is supposed to control and adjust the cycle time if the water is dirty but we cannot understand why it has increased so much without any noticeable changes in the quality of the water going into the washer or our cleaning of the plates cleaned by the washer.