key fragment drop rate

can there be an occurrence bonus on key fragments depending on how many boxes you have without any keys to open them? like maybe 1% per box? so if you are like me and have 8 boxes and no fragments, you have an 8% bonus, but if you have 8 boxes and 3 fragments or a key, you only get 7% its rediculous that i play several hours daily and i have had 7-9 boxes just sitting in my loot for the past 6 months that i can never get enough key fragments for