It is simple. Go do a autorotation with a empty machine(as they are originally set) and see how quick that rotor rpm climbs when you drop the collective to the stop. Now, without setting anything, put full fuel and load her to 2250kg. Now do the same dropping the collective onto the same bottom stop and watch that rotor rpm. If you blink you will be at 470rpm in a B3. We as a rule set the bottom stop at heavier weights as that is where we operate and you have to wind in that screw to the point were the collective lock can't reach anymore-in itself a massive problem for hyd checks. There is of course a balance which is easily reached during the maintenance procedure iaw the manual.
Bottom line, the heavier you are the faster that rotor will run before you pull back on collective-are you fast enough?-and then there is the aerodynamic forces involved without hydraulics at 2800kg vs 2250kg. The whole idea of the 2800kg is the extra load must be jettisonable! Remember not all external cargo on the Squirrel limits it to 80/60 knots as for instance the bomber kits does not require that drastic reduction in speed vs a bambi bucket on a sling so you could be bombing along at 110kts at 2800kg but still you can jettison the extra to ease the load and then reduce speed.