Learn English – the difference between “To finish something” and “To end something”

I would say the addition of the word “on” is more or less superfluous in almost every case. In other words, I believe later can always be substituted for later on, but not the other way around. When in doubt, later is the safe word to use.

For example,

We will have lunch now, and later on(or later) we will go to the park.

Where you can’t use later on:

I arrived later than she did.

See you later.

Later can be a way of saying goodbye, as a short form of “see you later”, but you can’t use “later on” in this way. Later and later on can both be thought of as short terms for “later on in time”.

To be picky: the nuance of "something else" implies an alternative; "something extra" implies an addition.

Examples: "I am allergic to peanut butter, so I need to use something else in my sandwich."

"I love to put something extra in my peanut butter sandwiches, like bananas."

So in the sentence in the question, I would use "extra" if I was being very picky; however, I think the colloquial understanding of "something else" would give the reader the same idea. In other words, I don't think the reader would see "something else" as implying that men were a different impetus as opposed to an additional impetus.