I have the old version but installed the "plus" control panel upgrade. I think the improvements are well worth it, especially when you have to contend with cold weather. In days gone by I sometimes struggled to reach 2nd crack within the normal roast time (300 g batch using 1 lb/400 g setting), especially if I was roasting outside on a chilly day. However the plus version allows you to extend the roast time indefinitely; by pressing the C button you get an additional 3 min 10 s roasting time.
As for making use of the manual setting of roast power, I've pretty much stuck to the 1 lb-P1 profile using 300 g of beans. If left to its own devices, the P1 profile is supposed to be 100% power for the entire roast period. When my roasts reach rolling 1st crack, I press the P4 button and this reduces power to 75%. I let it run at this level till start of 2nd crack and then cool. I have heard of others dropping power to 50% or lower at 1st crack, but haven't tried this lately with the cold weather (worried about stalling the roast). I'm not on top of the science behind it all, however I read that dropping the roast power this way allows you to stretch the roast time between 1st and 2nd crack. With the previous version some achieved this by propping open the door for a period of time. Being able to alter the roast power in the plus version seems a great improvement.