This yogurt makes a great non-sour starter for SCD legal yogurt if you can find it or an equivalent where you are:
astro.ca/products/astro_original_balkan_plain_750g_family_tub/#.UvvnhfnLrHoChances are the reason it's really sour is the addition of lacto bacteria in your starter powder or however you made it.
So the difference is the one above contains only the two necessary cultures for any yogurt product - Thermopolus and Bulgaris (however they are spelled). I emailed the company to verify as well. So any yogurt made from only these two cultures will have a smooth, non-sour taste.
Incidentally, you can see just how much sugar etc is added to commercial yogurt to get it to be non-sour. It's crazy.
If you use the above starter a teaspoon of honey makes it edible plain if you really want. Also it's the best to use for cooking.
I sometimes make yogurt with laco bacteria in it - but only use it to mix in fruit smoothies and such as it hides the sourness - even then it's still quite noticeable.