We're talking LOTS of 10+1 and not just a couple of rolls. That 11th roll still falls under the same rules as the single rolls, with the exception of it being a "free" roll. However, since you can't statistically evaluate a roll in fractions, then in order for the 11th roll to pay off as a whole, would require significant amount of 10+1 rolls.
In short, you're more than likely to roll a gold at current rates in any single roll, than see that "free" roll pay off. Unless Nutaku tweaks the chances on a 10+1 roll so that on average it works out to be a few % higher chance than a single roll.
Edit:
Put it in another way. You have just as many chances to roll 2 stars on a 10+1 compared with a single roll. People posting salts about 10+1 "miracle" rolls don't hear from people who also pulled singly and obtained 2-5 in a row miracles. Why? Because it's much harder to prove those kinds of screen captures and no one would bother to video cap each attempt.