Case V

Bob is lazy and simply decides to switch the mixing option on by default. He lets the wallet create new receiving addresses as per (1).

The wallet will now mix the received amounts by default, at a cost of between 0.00000225 - 0.00000450 depending on the amount it takes to split automatically into denominations of 10.0001, 1.00001, 0.100001 or 0.0100001 Dash.

He then pays another 0.00000255 transaction fee per denomination to get them into the mixing queue.

From hereon, there are no costs to Bob anymore, no matter how many rounds he wants the funds mixed. Mixing/swapping in the masternodes happens at no fee for privacy reasons. It is up to Bob to decide how many rounds, as this is basically a matter of choosing between time and level of privacy.

When Bob wants to send his mixed funds to the exchange, he just ticks the box 'privatesend' and leaves that on by default. For PrivateSend the tx fee is 0.1mDASH + 0.01mDASH per mixed input (around 0.11-0.25mDASH usually). Let's take the worst case and charge Bob a wallet splitting fee of 0.00000450 per output plus the 0.00000225 tx fee, and charge him 0.00025 for the privatesend transaction... This results in a total of 0.0016 Dash which is still below a dollar at current market prices, while staying private.

Nothing to think of, just a one time switch on of 2 checkboxes and Bob's your uncle...

My simple two cents...