These are not Loetz pieces. It is suspected that they may be Kralik, but I do not believe they have ever been nailed down for sure. They seem to appear with varying degrees of execution quality.
As far as your links go, the first link appears to be an example of Ausfuhrung 166. Neither the shape or the decor are related to Powolny. The great Powolny - Tango myth will likely never die.......
Your second link may be a Loetz piece, but could also be by a couple of other companies. In several instances that particular seller, who I am familiar with, applies numerous questionable attributions. As an example their "Extremely Rare Loetz Cypriote Vase" for $1100 is a nice example of Kralik Overshot.
Sue,
The term Tango has been applied to a wide variety of 2 color glass, but a relatively recent display in the Czech Republic of the glass and it's history reveals that the term initially referred to the multicolor combinations of the costumes worn by South American Tango dancers and encompassed much more than 2 color examples.......
Craig