My guru gave Bala diksha, at first, in 2007. He wanted to observe the progress and my sincerity in doing Bala japa before giving me initiation for the others. It took me more than 3 years of daily japa to complete one purascharana of Bala mantra. In 2010, my guru gave initiation of Soubhagya Vidya, Shodashi and Mahapadukanta Dikshas all at once. It was in 2011, after this initiation, I had achieved my life's dream job - which otherwise seemed impossible until then, as I have been unsuccessful in getting that job for the previous 5+ years.
Perhaps, getting the dream job can be said to be an outcome of the mantra siddhi of Bala. Whereas the higher Srividya mantras contain more syllables in them, and completing a purascharana would take several more years (than the 3 years that a purascharana of Bala mantra took). Does it really need a purascharana to get the mantra siddhi for any mantra?