Parallel processing offers several advantages. However, when processing times are allowed to vary, it can result in unpredictable job sequences. This issue must be addressed in assembly systems where it is necessary to match specific jobs with specific materials downstream. This research analyses job sequences after parallel processing and provides strategies for dealing with jobs getting out of sequence. One strategy involves re-sequencing materials using material buffers and another involves re-sequencing jobs using job buffers. A simple analysis determines the size of material buffers. The size of job buffers is estimated using analytical approximation and formulas fitted to simulation results.