New Line does not match Indent / Alignment of previous line.

I think I'm missing some fundamental aspects of how indentation and alignment formatting work.  I read over the code formatting section of the custom language development guide, but I couldn't find the answer there.  I wrote another post here a few days ago with more details. 

Long story short, here's an example of what code in my language should look like this when properly indented.  ("." and "->" represent leading spaces and tabs respectively in all examples.)

(main_operation
->(sub_op_1 param_1 param_2)
->(several (chained (ops 
->->param_3
->->param_4
->)))
)

Each line is always either one level deeper/shallower than the previous line or else on the same indentation level.

The getIndent method inside my Block implementation returns the expected result when I use Ctrl-Alt-L to format my document.  However, when I'm typing code inside the editor, new lines are not properly indented.  This is what happens.  Consider a very simple piece of code, with "|" representing my cursor on the end of line 2.

(main_operation
->param_1 |
)

When I hit enter, I want my cursor to move to line 3 and line up with the code on the previous line, like this.

(main_operation
->param_1 
->|
)

But instead of a full indent, the new line is just indented by a single space.  The cursor lines up with the text "main_operation" instead of indenting as expected.

(main_operation
->param_1
.|
)

If I immediately use Ctrl-Alt-L to format my document, I get the desired outcome with the cursor lined up with the previous line of code.

So, my question is, why doesn't the newly created line get the expected indentation?  Can I force the formatter to run after the new line is added?  

Bonus question: when I use an insert handler, the resulting text is not indented at all.  Again, can I force the formatter to run after my completion contributor is invoked?