As I mentioned earlier, there is no dangerous situation here and you can relax a bit. As I had also mentioned in the previous post, these readings can vary from test to test and we see that with this latest test. The Hb level is 2 points higher than in the previous test. This alone will rule out HbH disease (3-gene deleted alpha thalassemia). The RDW in the new test is considerably higher, and again this is why when tests are borderline, they must be repeated. An RDW this high is only seen in iron deficiency. Once it passes 18.9, alpha thal is ruled out. The HbF of 1.5% is slightly high, leading to the possibility of beta thal minor. However, the HbA2 is normally a bit higher in beta minor, except when iron deficiency is also present. Microcytosis would be present in both iron deficiency and beta minor. So, this may be a case of just iron deficiency or iron deficiency in a thal minor. The rise in Hb since the previous test could be the result of the iron therapy, or the previous test may have been done when the child was sick and the Hb had dropped. The key statement made in this report is "If iron deficiency is excluded, consider thalassemia trait."
My advice is to request a panel of tests called iron studies to determine the true iron status. Ask the hematologist to run these blood tests, as the possibility of thal minor being concurrent muddies the picture some, and you also need to know if progress has been made correcting the iron level. I would also suggest paying special attention to his diet and make sure that it is thoroughly nutritious and does not contain any empty calories like junk foods. A daily child's multivitamin is appropriate, also. Citrus fruit and juices are recommended for the vitamin C content, as this will aid in iron absorption.
I will be very interested in what the hematologist has to say. I do not think there is a serious problem here, and most likely things can be corrected with proper nutrition. It is important to get an answer of whether or not he is a thal minor, as this is extremely important later in life when he decides to have children. All minors need to make sure their partners have been tested for carrier status, as two carriers can produce a major and this is very serious and should be avoided if possible.