^ have you noticed that you're feeding less w/ the humics? due to the increased availablity.
I've actually heard mostly the opposite--because the uptake mediated by humics and fulvics is a bit different than normal uptake from a straight chemical fertilizer it may be using a bit of a "loop-hole" to get around some of the nute burn issues which can arise from overfeeding.
I haven't the foggiest how that might work or play out--and I have not used these myself. This is just second-hand knowledge.
@el boyo
Can't help you with the application rates--I would pester some of the organic dudes, they'd be my first stop.
They should be fine together--it is my understanding that humics and fulvics are actually very stable substances and resist degradation pretty damn strongly. That humics and fulvics can be separated from the same compost sample would seem to indicate that they can coexist with one another.
Think of it this way--these are the things that stabilize at the end of every biological pathway. It's basically fully broken down dead stuff. Living things extract chemical energy mostly by oxidative processes to yield lower energy compounds rather than high energy ones. This is essentially a progression from higher energy to lower energy states, with "stability" correlating to increasingly lower energy states. In a sentence, when biology is done with this stuff it's left in a very unreactive state--if it weren't, some type of life would've found a way to turn it into something else before it's ultimate release.
If you know anything about nuclear chemistry or physics, you'll know that many things degrade in to lead + something else.
The reason lead is so ubiquitous is that it's very very very stable and doesn't like to degrade at all. When nuclei are splitting--lead is one of the most "thermodynamically favorable" states for a daughter nuclei to take on, and so it does in mass quantities.