Chris as mentioned above the new value is approx 1.2. We do quite a few of these samples and a reading of up to 1.8 is normal. The trend is a very important feature ie the increase should be very gradual over time. Sharp increases indicate problems. As mentioned 2.7 would be an upper limit not to go over. Also look at your bearing metals ie lead,copper and tin for increases as the TAN increases. Often there is a direct relationship.