To answer your query - Most of that time buffer is to account for the network related latency associated with the transaction being confirmed in a block.
Thanks for clarifying. I think you could add this information to the website. At the moment, it looks a bit like the MPC protocol is rather slow.
Also: doesn’t the block time also depend on the target blockchain? Base should be much faster then? Maybe you could separately state the time it requires for the signing protocol to complete?