I started mining on XVG (where there is no DGB Scrypt mining on this pool).
1. Is there a way to calculate the difficulty settings for my Antminer L3+ on Verge?
2. Howcome I see 500.000+ in my miner config but on the pool status I reach no more then 400000khz
The pool doesn't know how fast the miner claims to be, it calculates hash rate based on shares received.
The L3+'s 504MH is based on ideal work - from experience, due to work restarts (new block) 450MH seems to be the achievable maximum based on the way the L3+ batches the work on the ASICs.
Miningpoolhub isn't great at showing historical share hash rate, just run it for a few days and look at the coins received on the dashboard to decide if it's worth mining there.
For me, fees are low - it's worth it

On wich coin are you mining here? Atm I am getting around 180-200 XVG a day.