Most manufacturers will certify aircraft up to 10 kts. tailwind or flaps up to 20 000 ft.or Take off thrust for up to 5 minutes, or 8200 ft. maximum field elevation, etc. to keep the cost of certification low, that doesn’t mean that the airplane can’t fly above this limits, as an example I can tell you that our 737s. are certified at 15 kts for take off and landing (sometimes landing with a tailwind is better than a low circle approach at night in rough terrain) or some airlines using high airport elevations can use their engines for 10 minutes at take off power in case of engine failure or take off and land at 13 000 ft. high fields.
This way the manufacturer keeps down the price of the aircraft for most airlines that do not need to operate under these conditions, and charges an extra fee to the airlines that need a special certification.
Certainly there is a limit, but not even the manufacturer may know it, maybe you can use flaps up to 26 000 or 28 000 ft, or 22 kts. tailwind, it is just to expensive to find out.
Ever wonder why the 737-400 or 500 can’t use flaps one for Take off like the 200 and 300, maybe it has to do only with certification cost and not with performance.
The more certification test they run the more expensive the aircraft they sell.