Yes, John, you've described an orderly moult starting near his head in the springtime and so a normal moult is expected. The pattern of moulting should be orderly and in the following progression (with some overlap): the inner primaries; the outer primaries; the secondaries and tail feathers, and finally the body contour feathers. It's usually symmetrical and is pacded so as to avoid loss of flight capacity at any time. It's difficult to describe these different feather areas but perhaps visualizing them will help: https://www.google.com/search?q=image+of+primaryfeathers+in+birds&rlz=1C1CHFX_enUS705US705&oq=image+of+primaryfeathers+in+birds&aqs=chrome..69i57.6122j0j7&sourceid=chrome&ie=UTF-8
Most important, be sure that his diet is excellent at this time so he'll have the necessary protein and calcium in his body to manufacture new feathers. Seeds should compose less than 20% of his diet. A diet of mainly seed and nuts has excessive fat, carbohydrates, and phosphorus; marginal protein; adequate vitamin E, and are deficient in amino acids, calcium, available phosphorus, sodium, manganese, zinc, iron, vitamins A, D3 (necessary for efficient absorption of calcium), K, and B12, riboflavin, pantothenic acid, choline, and available niacin. Ideally, a balanced pelleted diet such as can be found here: www.harrisonsbirdfoods.com or here: www.lafeber.com/pet-birds should be fed as well as hard boiled egg yolk, pancakes and cornbread, the tops of fresh greens, dairy products such as yogurt and cheese, fresh fruits such as apples, pears, melon, kiwi, and berries, vegetables such as broccoli, carrots, beets, asparagus, cabbage, sweet potato, and squash, and even tiny pieces of meat.
Please respond with further questions or concerns if you wish.