I personally don’t like using the measuring cup on top to melt butter, I strictly use it for measuring the popcorn kernels. I find it easier to melt my butter in a glass measuring cup in the microwave, easier to pour on the popcorn!
I would like to point out that different sizes, brands and types of popcorn kernels all act different while popping! When you are popping small kernels you are more likely to have the kernels pop out of the machine before they are popped (beware they are hot to the touch). And with small kernels the popcorn itself is lighter and once cooked all comes out of the popcorn machine. Big popcorn kernels don’t pop out of the machine as much while cooking and the popcorn itself is denser. The bigger/denser popcorn doesn’t always come out of the machine, it needs to be dumped out after it’s done cooking. You can experiment for yourself on different kinds of popcorn!
Overall my family and I are loving our new popcorn machine since our last one from the 1980’s finally bit the dust! We make popcorn almost every night and we recommend this machine!