The description of algorithm indentation is completed at the top of page 13. The final step described as "Subsubsubsubstep" is missing a period after the character "a" denoting it's position.
Note that steps at that depth, when they occur 'for real', are also formatted without that period. See, for example:
10.5.3 Function Declaration Instantiation
/ step 11.a.ii.1.a
12.6.4 The for-in and for-of Statements
/ Runtime Semantics: Labelled Evaluation
/ For In/Of Body Evaluation
/ step 3.e.iii.2.a
Ah, I hadn't noticed that. Since there was no explicit statement mentioning dropping the period starting at the fifth depth level and only one example of a dropped period I assumed it was a typo.
This is an oddity of how the list style is defined. Maybe some day I'll figure out how it fix it in Word
these were fixed somewhere along the way prior to rev18