Complex sentence: Choosing to work with Erik Rutan as a producer again after working with Mark Lewis on the previous album was partly because of convenience, enabling the band to stay focused during the recording process, although Rutan's previous work with the band was also a deciding factor.
Split into simpler sentences: Choosing to work with Erik Rutan as a producer again after working with Mark Lewis on the previous album was partly because of convenience. Although Rutan's previous work with the band was also a deciding factor.