Complex sentence: The combined total number of P108Cs and Ts built was approximately 16, but it is unclear precisely how many of either version, however, most of the P.108Cs were subsequently modified for use as military transport aircraft and could accommodate up to 60 passengers.
Split into simpler sentences: The combined total number of P108Cs and Ts built was approximately 16, but it is unclear precisely how many of either version. Most of the P.108Cs were subsequently modified for use as military transport aircraft and could accommodate up to 60 passengers.