Relax, you used a good buffer with ~20%

worm castings and vermiculite (EACH!) and that also adds good soil biology. Humus and clay (vermiculite) are badass buffers. I think you'll be fine.
If anything you went overboard on the buffers - just the worm castings is probably all that was needed.
Or half of each lol
I use a crazy hot soil with 6+ months of nitrogen in it but it's got worm castings, biochar, compost,, and a bunch of greensand - all of which buffer the excess nitrogen by bonding with it in the ammonium stage of the nitrogen cycle, keeping nitrate levels pretty optimal throughout the grow.
I'm guessing this is some super soil recipe they read online? At least mb120 is trying to grow organically