They may only ship twice a year to wholesale'ers, but I guarentee you they are in production year round. Machinests are hard to find in most areas (I'm one, and pretty familiar with the industry) and they aren't going to hire temps to make their stuff twice a year. I would imagine it to be a lot easier to continue manufacturing as usual year round, and deal with the hassles of shipping, ordering, and all that other hectic stuff twice a year. This would let them hire part time workers for a few weeks to help deal with the increased volume of shipping demands, while keeping their machinests and assmeblers busy year round.
Just my personal idea of what's going on based from my little experience in such areas.
George