It's a model airplane motor designed to swing a big propeller at moderate RPM without having to use a gear reduction box and is built for torque at reasonable speed while running off of a 4 to 6 cell (Li) pack. It is rated for a maximum of 70A of current when it has a propeller blowing air over it to keep it cool - don't dare run more amps then what I'm putting through it right now since it doesn't have as good of cooling as it had in its intended application or I'll at least cook my haul sensors if not the whole motor. Its running like its was designed to run with its peak power and efficiency points close together and near the top of its RPM range which is exactly what is needed for spinning a big model airplane propeller, works great for a mid-drive set-up with it geared down just right so that its peak power sweet spot is right at about 80-RPM pedal cadence and however much I spool up above that on my pedaling is all gravy pushing the motor into a higher efficiency range and gaining significant improvements in range as a reward for keeping my effort up. I've got a simple automobile type Amp gauge mounted right center of my bars and I can actually watch the needle fall as the motor pulls less from the battery as I push into the pedals and spool up and put more of the load onto myself and at the same time push them motors efficiency up.

Interesting what you had to share, though about deliberately running at lower amps in order to change the curve profile of a motor that wan't originally designed for having the two sweet spots that close together but then at least so far mid-drive motors in the kits or totally from scratch mid-drive builds building from the motor on up, at least the ones I've gotten my hands dirty on, seem to have the two sweet spots fairly close together in the upper end of the RPM range anyway. It looks like the motor you provide the graph of is a commercial hub-motor where as I never even bothered to check the sweet spots on one of those since its the mid-drives where knowing the sweet spots and adjusting the gearing between the crank and motor to match up with those sweet spots is important. Never thought the sweet spots on a hub motor were of much concern since I can't feel them like I can in the pedals of a mid-drive.