The start of that section, 7.3.4, gives more explanation. On its own it appears mandatory :
(The whole thing depends on traffic and commen sense)
Table 2 sets out the recommended broadcasts, but pilots may use discretion in determining the number and type of broadcasts they make. For example, when operating from a private or remote airstrip, a single broadcast declaring an intention to take-off and track in particular direction may be all that is required where there is no response to the initial transmission.
Table 2 – Recommended positional broadcasts in the vicinity of a non-controlled aerodrome