The numeric indicator must be used in the table you show. The statement about headings applies only to column headings -- the row headings are considered entries in the body of the table. If, however, you have to switch columns and rows because there is not room for the columns across the braille line, then the letters would become column headings and the numeric indicator would not be required. If you must use guide dots, then the numeric indicator would have to be used.
As to the comments following the steps of the solution, I simply follow the equation with the comment on the same line. If the statement didn't fit on the line, it would runover in the correct runover position for the equation. In the simbraille below, the full cells represent empty spaces. I couldn't make it do empty spaces.
[braille]w+32+w .k #40 ,write equ,n4 ,if "! 7 m1
==x wd runov] 9 cell #3_4
[braille]#2w+32 .k #40 ,-b9e l t]ms4
[braille]#2w .k #8 ,subtract #32 f ea* side4