The fuel nozzels at the number 15 and 16 positions are designed differently than the other 28 nozzles. They are also color coded differently than 26 other ones (The 2 which are attahced to the ignitors also have different p/n). Nozzles 15 & 16 have larger primary spray patterns. They are always going to provide more fuel. Fuel nozzles are designed to provide the most efficient spray patterns at high power settings. During descent when the throttles are at times idled and at much lower power settings, these nozzles with the extra fuel output provide flameout protection.
Most aircraft ignition/fuel systems do a little extra during the approach phases of flight to prevent flameouts at such a critical time (also during adverse weather). An example if high idle. When flaps are down, or mayeb gear down under certain altitudes on some aircraft - the engines will go into high idle. In some aircraft, ignition will be initiated with anti-ice on. All to prevent flameouts.