Hi, I'm new on here too and the dutching videos got my interest too!
I've completed the 14 day trial and have now subscribed for a year. The dutching programme works well for me. Just to give you feedback on my experience(s) so far.
If the "back" button is ticked, when the odds move up or down, the software immediately adjusts and so does the predicted profit. (make sure the refresh is on 200 millisecs for best speed).
If your stake is too big for the available amount, is goes unmatched and stays in the market. If unmatched, it gets' cancelled unless you alter it to keep in-play or take BSP. (I always take BSP for insurance if unmatched).
I find the predicted profit is only a guide, an accurate one, based on how your trying to use the staking. However, once you click "place bet", for me, it doesn't serve a purpose. My position is either matched or not. (mostly matched).
The selections not matched are either ones I've manually asked for better odds, or I've missed the best price, but will average out @ BSP when unmatched at the off.
I use target profit for my main selections, 0 loss (insurance) for others and set an acceptable loss for the less fancied ones. By doing this, I'm effectively making a book% on ones I want on my side, the dangers and take on the less fancied ones.
I got caught out on African Trader on the 4thMarch South 3.50! Backed from 16/1 down to 6/1! I set an acceptable loss, but it still smarts. Learned afterwards, on it's last run, it had been disqualified as it had ran as scribner creek! You couldn't make it up!
On your post, your stake most likely went unmatched and cancelled when the market went in-play. The predicted profit changes all the time, even more so in-play. Dealing with non-runners, with dutching, can throw things around a little too.