Speaking with IGN, Tabata explains he was simultaneously working on the development of both Final Fantasy Type-0 (then called Agito XIII) and Parasite Eve II sequel The 3rd Birthday. According to him, balancing both was a difficult task.
"The 3rd Birthday and Final Fantasy Type-0 are the titles that were in development at the same time," Tabata said. "In regards to cancelling, we actually came really close when management gave me direct orders to focus on developing The 3rd Birthday, requiring me to step away from developing Final Fantasy Type-0 for about a year."
He continued, praising the shift in focus as being "great," but admitting they "had to scale down the Final Fantasy Type-0 development and continue minimally." Tabata cites this incident as the one that caused him to avoid working on multiple large-scale projects at the same time.
Thanks to IGN.