W T F.
Usually 6 WEEKS is promised for working solutions, rather than 6 hours.
I've, however, used working solutions as old as 2-3 months without any problems, and never heard of problems. Mixed developers are quite robust and the instructions about a few weeks are conservative to be on the safe side. Actually, color developers may even last more than a year quite well if stored properly...
How would continuous (replenishing) labs do it at all if it didn't last but just hours? That would cause huge replenishment rates.
As I stated earlier, I would never buy anything from this company. I can see more and more reasons arising for my decision.