Since you are already here, I would be grateful to receive clarification.
I noticed that all your partners have a fixed (network) fee of 0.0007 BTC per address in addition to the regular service fee (which can vary).
What interests me is, how exactly this amount was determined and what part of the costs it covers (talking about those fixed 0.0007 fees)? I assume that it is your fee because all partners have the same amount for it.

Also, with the rise in the price of Bitcoin, this fee is certainly no longer negligible, it is currently around $50. Most of the competitors are much cheaper here, or we can consider this as your targeting of large transactions.