I the exact DC is rolled it counts as rolling the power score in the old system. It is possible to take 10 if the psionicist is not under pressure, but it is never possible to take 20 . As a rule of thumb time is measured in minutes if it would be possible to take 10 in the situation, and meassured in rounds otherwise. This goes for duration as well if duration is listed as a number of rounds . If duration is listed as a number of turns , each turn is 10 minutes of game time.
Preparation time is always in minutes if listed as rounds.
Psionic powers To figure out a characters skill modifier with a given power add her ranks in the given power to her ability modifier. To find which ability modifier to use, look up the Power Score in the powers description. If she is successful she pays 10 PSP to initiate the power. If she rolls 18 on the d20, something nice is going to happen. Sometimes the effectiveness of the power depends on how well the roll was made or what was rolled.