Page 207 describes the three levels a psyker can use his powers at. Under the push description, it states "Regardless of the test's result, the psyker will automatically generate a significant disturbance in the warp and must roll twice on Table 6-2: Psychic Phenomena, applying one or both results, depending on the psyker's nature as described in Table 6-1: Psychic Strength."
Ok so when a psyker pushes a power, he automatically rolls twice on the phenomena table. Fair enough. But what does the part mentioning "applying one or both results, depending on the psyker's nature" mean? It hints that this is clarified in table 6-1, but in that table no mention is made about rolling once or twice when pushing, for any of the levels.