Record into the uppercase register to append keys to an existing macro.
2 drills
Forgot the j: Register a already did its job on line 1, but it doesn't move to the next line. Append a j with qAjq, then run it on the remaining lines with a count.
Forgot a step: Register a does only half of the job: line 1 shows what it did. Append the missing step with qA, finishing line 1 and moving down with j, then replay the whole macro on the remaining lines.