I have not had that problem, i usually get more than 5 gallons in my cans as there all able to hold a premix for 2 stroke. I usually get 5.25 in my older cans i think and thats to the "safe" line and 5.5 if i fill them up to the spout. The only "new safty" can i own is a deisel and i really dont pay that close attention when i get it as my tractor only holds like 6 gallons so its not that important to me? I also sometimes will fill 2, 5 gallon cans when at the farm for a long weekend so even if the new one only held 4.5 and the old one held 5 its no big deal as that will get me like 16 hours on the tractor in itself!