Alfa oil gauges and particularly the sender units are notoriously unreliable.
The readings you quote are not unusual. If there has been no sudden change in the readings, you are very unlikely to have a problem.
My readings are somewhat lower than yours and have been for the past 76k miles!
Those are very healthy readings don't worry. As with all cars, ensure you change oil and filter as often as you can afford to and it will stay that way. (I get it done at local tyre place, they charge £35 for semi synth and it is worth paying them cos the filter on the 24v 164 is a PIG to get to).