They are a better model, depending on what you are looking for, recipe memory, hop addition reminder something like 9 steps which you don't really need with the modified malts of today, for me the best thing is the marking time at the end of the mash. I seem to always get to the end of the mash when my wife will ask me to do something, and it is always urgent. With the latest model which you have, at the end of mash it will wait until you are ready to proceed with the boil, the old model just ploughs straight into the boil ready or not.
You live close by to me so your boil off should be the same, no atmospheric differences, same diameter kettle, you have the insulating jacket so pretty much the same as mine. Doesn't make any difference the amount being boiled whether is 10 or 30 litres You could always check it yourself put 10 litres into the kettle and boil for 1 hour, and don't forget to make an accurate measuring stick.
I have both the forty and the fifty they both boil off at the same rate.