Silly me, but when dealing with aircraft operating limits, why do we need to be mudding the waters by using the Beaufort scale for winds and sea state, using a range of wind speeds per level? When aircraft limits are determined for takeoff/landing it is typically for the actual current conditions not a range, and is recalculated based on any changes. To me a limit is a set figure, in this case a speed, just as you have for a max range, max altitude, max speed, etc.
Further, operating a small lightweight aircraft in any kind of gusty wind conditions would never be a good idea. Due to the aircrafts lightweight, pilot response time, and thrust available all together can easily be exceeded by true gusting winds. If the max wind speed limit is 25 kts steady state, and you are operating in current conditions of 15 kts steady state with gusts to 25 kts, then it is very likely that you will not be able to compensate for those rapid changes in conditions to the extent that you can avoid loss of control or a crash. Just operating in 10 kts steady state with gust to 20 can make it an extremely challenging flying environment to avoid crashing the craft on takeoff/landing or in to nearby objects. Pilot judgement, experience, and aircraft performance capability are key factors in dealing with such challenging environments anyway. Just because the box, manual, or expert says the bird can fly in 30 kts does not mean you should, unless you have the experience, ability, and you are certain that your aircraft has the performance capability to work in that environment.